Michael Laing - Johnson Matthey Technology Review

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Michael Laing - Johnson Matthey Technology Review
VOLUME 52 NUMBER 4 OCTOBER 2008
Platinum
Metals
Review
www.platinummetalsreview.com
E-ISSN 1471–0676
E-ISSN 1471–0676
PLATINUM METALS REVIEW
A Quarterly Survey of Research on the Platinum Metals and
of Developments in their Application in Industry
www.platinummetalsreview.com
VOL. 52 OCTOBER 2008 NO. 4
Contents
Thermophysical Properties of L12 Intermetallic
Compounds of Iridium
208
By Yoshihiro Terada
Platinum Group Metal Chemistry of
Functionalised Phosphines
215
By Martin B. Smith
EuropaCat VIII: “From Theory to Industrial Practice”
222
A conference review by Emma Schofield, Nadia Acerbi and Cristian Spadoni
“Catalysis for Renewables:
From Feedstock to Energy Production”
229
A book review by John Birtill
Platinum Group Metals Patent Analysis and Mapping
231
By Richard Seymour
Creep 2008: 11th International Conference on Creep and Fracture
of Engineering Materials and Structures
241
A conference review by J. Preußner, R. Völkl and U. Glatzel
Global Release Liner Industry Conference 2008
243
A conference review by Andrew J. Holwell
“The Periodic Table: Its Story and Its Significance”
247
A book review by Michael Laing
John Ward Jenkins
249
A tribute by S. E. Golunski
Abstracts
251
New Patents
254
Indexes to Volume 52
256
Acting Editor: David Jollie; Editorial Assistant: Sara Coles; Senior Information Scientist: Keith White
Platinum Metals Review, Johnson Matthey PLC, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.
E-mail: [email protected]
DOI: 10.1595/147106708X361321
Thermophysical Properties of L12
Intermetallic Compounds of Iridium
THERMAL CONDUCTIVITY AND THERMAL EXPANSION OF Ir3X FOR ULTRA HIGH-TEMPERATURE
APPLICATIONS
By Yoshihiro Terada
Department of Materials, Physics and Energy Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan;
E-mail: [email protected]
Thermal conductivity and thermal expansion for the intermetallic compounds Ir3X (X = Ti,
Zr, Hf, V, Nb or Ta) were measured in the temperature range between 300 and 1100 K. The
thermal conductivities of Ir3X are distributed in the range from 41 to 99 W m–1 K–1 at 300 K,
while the difference of thermal conductivities becomes less emphasised at higher temperatures.
The coefficient of thermal expansion (CTE) values of Ir3X are insensitive to temperature,
and fall around 8 × 10–6 K–1 at 800 K. The Ir3X intermetallic compounds with X = Ti, Zr, Hf,
Nb or Ta are suitable for ultra high-temperature structural applications due to their higher
thermal conductivities and smaller CTE values.
The L12 intermetallic compounds based on iridium (Ir3X) have been pursued as the next
generation of high-temperature structural materials
(1–6). The advantages of Ir3X are summarised as
follows. Firstly, the melting points are between 600
and 1000 K higher than those of nickel-based
superalloys (7). Secondly, an L12 crystal structure
offers the possibility of enhanced ductility as a
result of the large number of possible slip systems.
Finally, the two-phase γ/γ' type microstructure
formed in Ni-based superalloys can also be produced in Ir-based alloys (8–10).
Thermal conductivity and thermal expansion
are key parameters to evaluate the suitability of
metallic materials for high-temperature structural
applications (11, 12). Rapid heat transfer afforded
by high thermal conductivity enables efficient
cooling, which suppresses the appearance of lifelimiting heat-attacked spots (6). A smaller thermal
expansion is desirable to avoid thermal fatigue by
cyclic thermal conditions, since thermal stress
depends directly on the magnitude of the thermal
expansion. However, no data on the thermal properties of Ir3X are available in the literature.
The Ir-based compounds Ir3X form an L12
crystal structure when the partner component X
belongs to Group 4 or 5 of the Periodic Table
Platinum Metals Rev., 2008, 52, (4), 208–214
(13–15). The present study was conducted to
provide the data for thermal conductivity and
thermal expansion of Ir3X (X = Ti, Zr, Hf, V, Nb
or Ta) which serve to evaluate the suitability of
the compounds for high-temperature structural
applications. The alloy compositions prepared in
this study are given in Table I, together with the
compositional range of the L12 phase at the
homogenised temperature (1573 K) (7). The stoichiometric composition was chosen for each
compound except Ir3Hf. Note that the composition close to stoichiometry with L12 single phase
was selected for Ir3Hf, since an L12 single
phase is not achieved at the stoichiometric
composition.
Thermal conductivity measurements were performed by the laser flash method in vacuum in the
temperature range between 300 and 1100 K, using
a disc specimen of diameter 10 mm and thickness
2 mm (16). A short duration laser pulse is emitted
from a ruby rod onto the surface of the disc specimen. The temperature change on the other side of
the specimen was measured over time by both an
infrared detector and a type R thermocouple.
From the temperature-time profile, thermal conductivity was obtained (17). Thermal expansion
measurements were made using a dilatometer
208
Table I
Chemical Composition of the Ir3X Compounds Used in This
Investigation, Together with the Composition Range of the L12 Phase
at the Homogenised Temperature (1573 K) (7)
Compound
Ir3Ti
Ir3Zr
Ir3Hf
Ir3V
Ir3Nb
Ir3Ta
Nominal composition,
at.%
Composition range of L12 phase
at 1573 K, at.%
Ir-25.0Ti
Ir-25.0Zr
Ir-24.4Hf
Ir-25.0V
Ir-25.0Nb
Ir-25.0Ta
23.6–26.7Ti
22.2–25.5Zr
23.5–24.5Hf
22.6–36.1V
24.0–32.0Nb
24.6–27.2Ta
which consists of an alumina pushrod driving a
linear voltage differential transformer (LVDT)
(18). Dilatometer specimens were normally 3 mm
square and 8 mm long. Thermal expansion tests
were conducted over the temperature range from
300 to 1100 K at a heating rate of 10 K min–1 in an
argon atmosphere.
Thermal Conductivity
Figure 1 shows the thermal conductivities of
Ir3X compounds as a function of temperature.
The thermal conductivity tends to decrease with
increasing temperature for Ir3Nb and Ir3Ta,
which have thermal conductivities above
80 W m–1 K–1 at 300 K. Conversely, a continuous
increase in thermal conductivity with increasing
temperature is observed for Ir3V, which has a
smaller thermal conductivity at 300 K. The thermal conductivities of Ir3Ti, Ir3Zr and Ir3Hf are
rather insensitive to temperature. The thermal
conductivities of Ir3X at 300 K are widely distributed in the range from 41 to 99 W m–1 K–1, while
the difference becomes less emphasised at higher
temperatures.
Fig. 1 Thermal
conductivity
versus
temperature for
Ir3X (X = Ti, Zr,
Hf, V, Nb or Ta).
Note that the
value of Ir3Hf is
the offstoichiometric
data
Thermal conductivity, λ, W m–1 K–1
Ir3Nb
100
Ir3Ta
Ir3Zr
Ir3Ti
Ir3Hf
50
Ir3V
0
500
1000
1500
Temperature, K
Platinum Metals Rev., 2008, 52, (4)
209
The temperature coefficient of thermal conductivity, k, in the temperature range between 300 and
1100 K can be estimated from Equation (i):
k = (1/λ300 K)(dλ/dT)
≈ (1/λ300 K){(λ1100 K–λ300 K)/(1100–300)} (i)
where λ300 K and λ1100 K are the thermal conductivities at the temperature indicated by the subscript.
The temperature coefficients of Ir3X are plotted
against the thermal conductivity at 300 K in
Figure 2, together with the plots for pure metals
(19–21) and intermetallic compounds (22–24).
As a general rule, the thermal conductivity and
the temperature coefficient are inversely correlated
in pure metals and intermetallic compounds. All
the Ir3X compounds other than Ir3V are characterised by larger thermal conductivities and smaller
temperature coefficients. In particular, the thermal
conductivities of Ir3Nb and Ir3Ta are nearly equal
to that of NiAl, which is widely recognised as a
high thermal conductivity compound (17, 25).
The thermal conductivity of an intermetallic
compound is quantitatively correlated with those
of the constituents of the compound though
Nordheim’s relation (26). The high thermal conductivities of Ir3X may be partly due to the high
thermal conductivity of pure Ir, whose thermal
conductivity at 300 K is 147 W m–1 K–1.
Ir3X
34.1
25
f.c.c.
b.c.c.
h.c.p.
L12
B2
Other crystal structures
CoGa
Temperature coefficient of thermal conductivity, k, 104 K–1
20
Pt3Ge NiTi
15
NiGa
Rh3Ti
Ni2Al3
10
Pt3Ga
Pt3Ti
5
FeAl
0
–5
Ni3Al
Ir3V
Pd
V
Rh3V Nb
Ni3Ge
Ni3Ga
CoTi
CoAl Ir3Hf Pt NiAl
Zr
Ir3Zr
NiAl3
Ta
Ti
Ir3Ti Os Ir3Nb
Rh
Hf
3
Ir
Hf
Re Rh3Zr
Rh
Ru Mo
Ir3Ta
Ni3Ti
Rh3Ta Cr Rh3Nb W
FeTi
Au Cu
Ag
Be
–10
3
5
7
10
20
30
50
70 100
200
300
Thermal conductivity at 300 K, λ300 K, W m–1 K–1
500
700 1000
Fig. 2 Correlation between thermal conductivity at 300 K and temperature coefficient for Ir3X. The data for pure
metals (19–21) and intermetallic compounds (22–24) are also indicated
Platinum Metals Rev., 2008, 52, (4)
210
Thermal Expansion
Table II
Results of the thermal expansion measurements (ΔL/L) are shown in Figure 3. The
dilatation curves for all the Ir3X compounds are
smooth functions of temperature exhibiting no
sudden changes in slope. The curves in Figure 3
reveal that the thermal expansion of Ir3Ta is
slightly smaller than that of either Ir3V or Ir3Nb
over the temperature range between 300 and
1100 K. Also, the data indicate the smaller thermal expansion of Ir3Ti in comparison with those
of Ir3Zr and Ir3Hf.
The slope of the curve of ΔL/L vs. temperature
is the CTE. The relatively flat dilatation curve for
each compound indicates that the CTE of Ir3X are
insensitive to temperature in the range 300 to
1100 K. The CTE of Ir3X compounds at 800 K
are summarised in Table II. All the values of CTE
are concentrated around 8 × 10–6 K–1. The largest
CTE is found in Ir3V with 8.4 × 10–6 K–1, while
Ir3Ti shows the smallest at 7.5 × 10–6 K–1.
Figure 4 shows the correlation between the
CTE at 800 K and the melting point for Ir3X,
together with the plots for pure metals (21, 27) and
intermetallic compounds (22, 28). It is found that
Coefficient of Thermal Expansion of Ir3X
Compounds at 800 K
Compound
Coefficient of thermal expansion
at 800 K, K–1
7.5 × 10–6
8.2 × 10–6
8.2 × 10–6
8.4 × 10–6
8.0 × 10–6
7.6 × 10–6
Ir3Ti
Ir3Zr
Ir3Hf*
Ir3V
Ir3Nb
Ir3Ta
*Note that the value of Ir3Hf is the off-stoichiometric data
all the plots of pure metals and intermetallic compounds including Ir3X are arranged by a universal
curve, irrespective of crystal structure. The CTE
of Ir3X are approximately equal to that of pure Ir
and one half those of conventional intermetallic
compounds such as Ni3Al and NiAl. The smaller
CTE values of Ir3X correlate well with the higher
melting points of the compounds.
The interatomic force in metallic materials is
characterised by cohesive energy, Ecoh, defined as
the difference between the potential energy of
atoms in the gas state and that in a crystal of the
1.0
1.0
0.5
Ir3Ti
Ir3Zr
ΔL/L, %
Ir3Hf
Fig. 3 Thermal
expansion of Ir3X during
heating from 300 to
1100 K. The heating rate
is 10 K min–1. Note that
the curve of Ir3Hf is the
off-stoichiometric data.
Left-hand axis: Ir3V,
Ir3Ta, Ir3Nb
Right-hand axis: Ir3Hf,
Ir3Ti, Ir3Zr
ΔL/L, %
0
0.5
Ir3V
Ir3Nb
Ir3Ta
0
300
400
500
Platinum Metals Rev., 2008, 52, (4)
600 700 800 900
Temperature, K
1000 1100
211
40
Ir3X
f.c.c.
b.c.c.
h.c.p.
L12
B2
D019
Mg
Coefficient of thermal expansion, α, 10–6 K–1
Al
30
AgMg
Ag
20
10
FeAl
Cu
CoGa
Be
NiGa Ni Sn
3
Ni
Ni3In Au
Fe NiAl
Co
Ni3Al
Ni3Ga Ni3Ge
Rh3Zr
Ni3Si
Pd CoAl
FeTi Y Rh3V
Rh3Hf
NiTi
V
Ir3Zr
Ti Cr Rh
CoTi
Ir3V
Rh3Ti CoHf Pt
Ir3Hf
Rh3Nb Zr
Ta
Ir3Nb
Ir
Re
Ir3Ti Hf Ir3Ta
Rh3Ta
Os
Mo
W
0
1000
2000
3000
Melting point, Tm, K
4000
5000
Fig. 4 Correlation between coefficient of thermal expansion at 800 K and melting point for Ir3X. The data for pure
metals (21, 27) and intermetallic compounds (22, 28) are also indicated
material. The cohesive energy in intermetallic
compounds is expressed as the sum of the sublimation energy of the alloy, Esub, and the heat of
formation of ordered structure, ΔH (29),
Equation (ii):
Ecoh = Esub + ΔH
(ii)
Table III summarises the Ecoh, Esub and ΔH values
for the Ir3X compounds, where Esub was obtained
from the data source (30) and ΔH was calculated
from Miedema’s formula (31, 32). The data for
Ni3Al and NiAl are also indicated in Table III. It
can be seen that the cohesive energy of intermetallic compounds originates mostly from the
sublimation energy rather than the heat of forma-
Platinum Metals Rev., 2008, 52, (4)
tion of ordered structure. The cohesive energy for
Ir3X is located around 700 kJ mol–1, which is 1.7
times larger than that of Ni3Al and NiAl. The
larger cohesive energy of Ir3X would result in the
higher melting point and in the smaller CTE of the
compounds.
Conclusions
Thermal conductivity and thermal expansion of
Ir3X (X = Ti, Zr, Hf, V, Nb or Ta) were surveyed
in the temperature range between 300 and 1100 K.
The thermal conductivity and the temperature
coefficient are inversely correlated for Ir3X. All the
Ir3X compounds other than Ir3V have larger thermal conductivities and smaller temperature
212
Table III
Cohesive Energy, Sublimation Energy and Heat of Formation for Ir3X,
Ni3Al and NiAl
Compound
Cohesive energy,
Ecoh, kJ mol–1
Ir3Ti
Ir3Zr
Ir3Hf
Ir3V
Ir3Nb
Ir3Ta
Ni3Al
NiAl
675
732
728
662
737
749
436
426
Sublimation energy*,
Esub, kJ mol–1
Heat of formation**,
ΔH, kJ mol–1
620
653
658
631
685
698
403
378
55
79
70
31
52
51
33
48
*Sublimation energy is obtained from the data source (30)
**Heat of formation is calculated from Miedema’s formula (31, 32)
coefficients. The CTE of Ir3X compounds are
insensitive to temperature, and fall around 8 × 10–6
K–1 at 800 K. The smaller CTE of Ir3X are well
correlated with the higher melting points of the
compounds. The L12 intermetallic compounds
Ir3X with X = Ti, Zr, Hf, Nb and Ta are characterised by larger thermal conductivity and smaller
thermal expansion.
References
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Technology, Hokkaido University, Sapporo, 1998,
p. 699
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Honolulu, Hawaii, 12th–16th July, 1998, eds. M. A.
Imam, R. DeNale, S. Hanada, Z. Zhong and D. N.
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The Author
Yoshihiro Terada is an Associate Professor in the
Department of Materials, Physics and Energy
Engineering, Nagoya University, Japan. His main
activities are in the thermal and mechanical
properties in metallic materials for high-temperature
applications. His major field of present interest is the
creep mechanisms of heat resistant magnesium
alloys.
Platinum Metals Rev., 2008, 52, (4)
214
DOI: 10.1595/147106708X361493
Platinum Group Metal Chemistry
of Functionalised Phosphines
PROPERTIES AND APPLICATIONS OF THEIR COORDINATION COMPLEXES
By Martin B. Smith
Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.;
E-mail: [email protected]
Tertiary phosphines are a large class of fascinating ligands commonly used in platinum group
metal (pgm) coordination chemistry. They play an important role in areas ranging from
homogeneous catalysis to selective metal extraction chemistry and to therapeutic applications.
In this article, pgm-containing complexes of new functionalised mono-, di- and polytertiary
phosphines, derived from straightforward condensation reactions, are reviewed. These
phosphines have been used as building blocks in supramolecular chemistry and for constructing
novel hexanuclear pgm complexes, as ligands for bridging homo- and heterobimetallic late
transition metals, and in the field of precious metal-based catalysis.
Tertiary phosphines arguably remain the linchpin of much of our understanding about
coordination chemistry, catalysis and other applications using metal complexes. Their extreme
flexibility originates from the ease with which their
steric and electronic properties, bite angle, solubility and chirality can be regulated in a precise and
controlled way. Trivalent phosphorus ligands have
frequently been used in coordination and
organometallic chemistry as a means of stabilising
the metal centre, typically a pgm. Tertiary phosphines can dictate the coordination number of a
metal centre. For example, low-coordinate linear
or trigonal planar geometries can be stabilised by
bulky ligands such as tricyclohexylphosphine
(PCy3) and tri(tert-butyl)phosphine (P(tBu)3).
Furthermore the electronic properties, and hence
reactivity, of the metal centre can be influenced by
substituents bound to the phosphorus donor
atom. In our research group at Loughborough
University, we have been interested in phosphorus
H2
C
N
H
H
R
HO
–- H2O
PR2
N
H
PR2
C
H2
R
ligands for over a decade. In this article, some of
our recent achievements are reviewed, along with
contributions from others, in this stimulating field
of pgm chemistry.
The preparative strategy for ligands 1 and 2,
illustrated in Scheme I, relies on an established
variant of the classic Mannich condensation reaction (1). In our work, many ligands of both types
have been synthesised in high yields by a single
step procedure, using a phosphorus-based
Mannich condensation (PBMC) reaction.
Adaptation of this simple methodology to nonsymmetric ditertiary phosphines will also be
discussed. Our initial contribution to this field
stemmed from reports (2, 3) that diphenyl-2pyridylphosphine (Ph2P(2-C5H4N)) could be used,
in conjunction with simple palladium(II) salts and
a strong acid, typically p-toluenesulfonic acid (pMeC6H4SO3H), as an efficient homogeneous
alkyne carbonylation catalyst system. Drent et al.
(2) proposed that the 2-pyridyl (2-C5H4N) group is
H2
C
HO
PR2
–- H2O
1(1)
R2 P
N
C
H2
PR2
C
H2
R
2
(2)
Scheme I Synthetic approaches to new aminophosphine ligands 1 and 2
Platinum Metals Rev., 2008, 52, (4), 215–221
215
necessary for two reasons. Firstly, it facilitates the
carbonylation of alkynes by accessing different
coordination capabilities of Ph2P(2-C5H4N), using
the phosphorus and/or nitrogen donor atoms.
Secondly, it acts as a ‘proton messenger’ through
an intermediate Pd(II) species bearing a pendant
pyridinium group. We have prepared new functionalised pyridylphosphines and investigated their
ligating properties to pgms (4). As will be shown,
hydrogen bonding, invariably using the secondary
amine group, was a key aspect. Its action was
characterised through crystallographic solid-state
studies. Using the PBMC approach illustrated in
Scheme I, the first ligand synthesised was 3a.
Phosphine 3a and its derivatives 3b and 3c exhibited a plethora of coordination modes
(monodentate, chelating, bridging) when complexed to an array of pgms such as ruthenium(II),
rhodium(III), iridium(III) and platinum(II).
X
H
N
N
PPh2
X
X
X
X
=
=
=
=
OH
OP(O)Ph2
OPPh2
H
3a
(3a)
3b
(3b)
3c
(3c)
(3d)
3d
Recently, phosphine 3d was shown to bridge
two dichloropalladium(II) (Cl2Pd(II)) metal centres
in a head-to-tail fashion (Figure 1), affording the
12-membered metallocycle 4 (5, 6). One feature we
routinely observed when closely related
pyridylphosphines were studied by single-crystal
X-ray diffraction (XRD) was the presence of
4
Fig. 1 Single crystal X-ray structure of palladium(II)
phosphine complex 4
Platinum Metals Rev., 2008, 52, (4)
intermolecular H-bonded dimer pairs involving the
secondary amine (–NH) group (7). These early
findings prompted us to probe in more detail these
secondary interactions with other pgm complexes
of functionalised tertiary and ditertiary phosphines.
In particular, the ability of carboxylic acids to associate through H-bonding led us to design and
synthesise new ligands for supramolecular chemistry and crystal engineering.
Crystal Engineering
Given the versatility of tertiary phosphines, we
were intrigued to find that their use in supramolecular chemistry is often reserved to that of
spectator or ancillary ligand (8). Our efforts to
study the solid-state packing behaviour of an isomeric series of metal complexes containing
phosphorus-based ligands were thwarted by a lack
of suitable examples in the literature. With this in
mind, and identifying commercially available isomeric amines with hydroxyl/carboxylic acid
groups as attractive reagents, a range of highly
functionalised ditertiary phosphines were synthesised using a PBMC route (Scheme I). These were
isolated in good to high yields and complexed to
afford an isomeric series of seven square-planar
dichoropalladium(II) compounds. Crystallographic
studies showed that these complexes H-bond in a
manner highly dependent on the disposition of the
functional groups on the N-arene ring. Some of
the isomers are shown in Figure 2. Solid-state
structures are formed, composed of 20-membered
dimer pairs, 5a, 1D-polymeric chains, 5b, or ladders, 5c, containing 38-membered rings (9).
More strikingly, changing the labile Pd(II)
source from PdCl2(cod) to Pd(CH3)Cl(cod) (cod =
cycloocta-1,5-diene) afforded the novel self-assembled hexameric Pd compound 6 in high yield (10).
In this example, the ligand bridges two Pd(II)
metal centres via an unusual P2O-tridentate coordination mode to give a large 48-membered
metallocycle possessing a unique hexagonal
arrangement. Other hexameric analogues, of
nanometre dimensions, have also been reported
(10). Self-assembly, using a range of H-bonding
interactions, have also been studied in linear
gold(I) complexes (11) and half-sandwich
216
O
H
OH
N
O
Cl
Cl
P
Pd
P
P
Cl
P
Cl
P
P
Cl
Cl
O
OH
HO
H
O
O
N
P
Cl
N
Pd
Pd
Cl
H
O
P
P
Cl
N
Pd
OH
N
Pd
O H
Cl
O
P
O H
OH
O
5b
(5b)
5a
(5a)
HO
Cl
Cl
Cl
Pd P
P
O
H
Cl
N
Cl
Pd
P
P
O
H
Pd
Cl
N
O
N
P
P
H
O
O
Cl
P
O
N
P
Pd
O
P
Pd
HO
N
P
Cl
O
O
O
O
O
OH
O
H
H
H
H
H
H
O
O
O
O
O
O
O
N
P
H
O
P
N
Cl
O
P Pd
H
Cl
P
Cl
P Pd
Cl
N
H
O
5c
(5c)
Cl
O
Pd P
P
N
OH
Cl
P
N
N
O
P Pd Cl
O
O
P
Cl
P Pd
Cl
OH
P
Pd
Cl
P
Pd
P
O
O
O
N
O
OH
6(6)
Fig. 2 Structural motifs of different square-planar palladium(II) phosphine complexes 5a–5c and 6. Phenyl groups on
phosphorus (pink) are omitted for clarity and dashed lines indicate hydrogen-bonding contacts
organometallic Ru(II) complexes (12) using our
isomeric phosphine ligands. This area of pgm tertiary phosphine chemistry, coupled with
controlled H-bonding capabilities, coincides with
new interest in supramolecular-based pgm
catalysts (13).
Mixed Metal Complexes
Symmetric diphosphines are normally known to
use both phosphorus donor sites for coordination,
thereby forming a classic chelate ring. We were
interested in investigating whether, by manipulating
the ligand structure, it would be possible to
sequentially coordinate a metal centre at one P-donor
site, then add a second metal centre to the remaining
noncoordinated position (14). To accomplish this,
our PBMC approach was modified such that two
sterically dissimilar P-based groups (P1 and P2) could
be introduced in two consecutive steps (Scheme
II, Steps (a) and (b)). By choosing suitable pgm
precursors,
for
example
dichloro(pcymene)ruthenium(II) dimer [RuCl2(p-cymene)]2,
or a dichloropentamethylcyclopentadienyl metal
dimer [MCl2(Cp*)]2 (M = Rh, Ir), novel
Platinum Metals Rev., 2008, 52, (4)
organometallic ‘piano-stool’ complexes were
obtained (Scheme II, Step (c)). These ‘metalloligands’
were used to prepare heterobimetallic complexes
(Scheme II, Step (d)) with distinct metal
combinations such as Ru(II)/Au(I) or Ir(III)/Au(I),
7. A recent extension to this work, using a new
nonsymmetric ligand incorporating –PPh2 and –PAd
groups (PAd = phosphaadamantane), allowed us to
prepare Ru2Pd and Ru2Pt trinuclear complexes, in
which the square-planar PdCl2 or PtCl2 metal centres
have two bulky phosphaadamantane cages trans to
each other (15).
Supported P–C–N–C–P Catalysts
Complexes of the pgms are extremely valuable
as catalysts for many homogeneous catalysed reactions in the chemical and pharmaceutical
industries. While homogeneous catalysis offers
many rewards over heterogeneous catalysis, its
major handicap is the requirement to separate the
catalyst from (by)products and unused reactants.
This has important industrial implications, affecting the economic viability of a process.
Modification of the skeletal P–C–N–C–P frame-
217
P1
R
NH2
R
P2
P1
(a)
(a)
NH
R
P1
(b)
(b)
N
P2
[M]
(c )
(c)
R
P1
Cl(1)
N
P2
Au(1)
P(1)
(d)
[M´]
[M`] (d)
O(1)
C(25)
C(19)
C(12)
[M]
C(11)
N(1)
P(2)
C(18)
C(4)
Ir(1)
C(1)
O(3)
R
P1
N
Cl(3)
P2
Cl(2)
O(2)
[M´]
[M`]
7(7)
[M]
Scheme II Cartoon illustration showing the synthesis of mixed metal dinuclear phosphine complexes (P1 and P2 are Pbased groups). The insert shows an X-ray structure of the heterobimetallic phosphine complex 7
work of ligand 2, shown in Scheme I, has enabled
phosphines to be studied in homogeneous catalysis, and allowed the development of new methods
for the separation of the pgm catalyst. The variety
of these ligands will be illustrated later in this article, and hinges on the tunability of the R group on
the central N atom, rather than on the P donor
atoms as discussed previously. This facilitates
attachment to different solid supports. The following examples serve to illustrate some recently
published approaches, and highlight the importance of using chelating diphosphines to aid
catalyst stability. Lu and Alper (16) showed how
the recovery and recycling of catalysts could be
realised using dendrimers peripherally decorated
with catalytically active Pd(II) metal centres, supported on silica gel. The preparation of dendrimer
complexes on silica, such as 8, involved first synthesising the diphosphine by reaction of the
appropriate primary amine with (hydroxymethyl)then
diphenylphosphine
(Ph2PCH2OH),
complexing using the labile Pd(II) complex
PdCl2(PhCN)2. These Pd-based dendrimers were
used for the intramolecular cyclocarbonylation of
Cl
Ph 2
P Pd Cl
N
O
Silica
support
O
Si
(CH2) 3
Ph2
PPh
N
Ph
N
8(8)
Platinum Metals Rev., 2008, 52, (4)
PPh 2
Cl
Pd
P
Ph 2 Cl
Pd
R2
P
N
O
Cy2
P
AcO
OAc
AcO
P
Cy2
Cy
AcO
Cy2
P
Pd
P
R2
OAc
N
Pd
RR == Ph,
Ph,CyCy
9(9)
AcO
N
N
(CH23)44
(CH
N
Cy2
OAc
P
Pd
OAc
P
Cy2
Cy
N
Cy2
OAc
P
Pd
OAc
P
Cy2
Cy
N
P
Cy22
Cy
Pd(Pd
4-10
4-10)
(Pd8 and
Pd16
not
(Pd 8 and
Pd 16
notshown)
shown)
218
iodinated aryl amines and various 12- to 18-membered ring macrocycles were generated.
Dendrimer complexes such as 8 attached to silica
gel permitted simple filtration and reuse (up to
eight times) without any significant diminution in
catalytic activity.
On a similar theme, the monomeric complex 9
and metallodendrimer Pd4-10, along with two
higher generations related to Pd4-10, were found
to be efficient catalysts for Suzuki coupling reactions of chloro- and bromoarenes (17). Recovery
and reuse was possible with the dendrimer-based
Pd catalysts, while recovery of the single metal site
complex 9 was hampered by rapid decomposition,
affording a catalytically inactive black precipitate.
Two independent research groups (18, 19)
have prepared the silica-supported P–C–N–C–P
diphosphine catalyst 11 using the PBMC ligand
synthesis strategy shown in Scheme I. Long and
coworkers (18) loaded the supported catalyst 11
into standard teflon tubing and performed carbonylative cross-coupling reactions with different
aryl halides and benzylamine. The microtube reactor permitted catalyst reuse for a number of
cycles. 11CO radiolabelled amides could also be
synthesised by this method. Uozumi and Nakai
(20) prepared a supported diphosphine from
ArgoGelTM-NH2 (from Argonaut Technologies
Inc, now owned by Biotage AB) and
Ph2PCH2OH, and characterised the product by
gel-phase 31P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopic
studies. Reacting the diphosphine with the allylpalladium dimer [PdCl(η3-C3H5)]2 in toluene at
25ºC for 15 min gave complex 12. In aqueous
potassium carbonate, complex 12 was an effective
catalyst for the Suzuki-Miyaura coupling of aryl
halides and aryl- or vinylboronic acids and could
be reused up to three times. Employing the same
tactic for attachment to solid supports, treatment
of the commercially available ArgoGelTM amine
resin with diphenylphosphine/paraformaldehyde
(Ph2PH/(CH2O)n), followed by addition of
[Ru6C(CO)17], gave compound 13 as dark red
beads (21). No catalytic data was reported for 13;
however, phosphine-free [Ru6C(CO)17] variants
were shown to be promising hydrogenation catalysts for cyclohexene.
Related phosphine-modified ArgoGelTM
amine-based compounds, in this instance containing the pentaruthenium cluster [Ru5C(CO)15],
were shown to act as gas sensors for hydrogen
sulfide (H2S), carbon monoxide (CO) and sulfur
dioxide (SO2) (22). Changes were monitored by
Fourier transform infrared (FTIR) spectroscopy
and by colour changes of the beads prior to and
after
gas
addition.
Furthermore
the
TM
ArgoGel -NH2 resin was used to prepare sup−
O
Silica
support
Si
O
N
OEt
Et
Ph 2
Cl
P
Pd
P
Cl
Ph 2
ArgoGel
res in
resin
Ph 2
P
O
O
O
Ph2
P
(CH 2)2
[Ru6C(CO)17]
N
n
P
Ph
Ph22
ArgoGel
resin
N
Ph2 Cl Ph2
P
P
Ru
N
P
P
Cl
Ph
Ph
Ph22
Ph22
13
(13)
ArgoG el
resin
+
+
Pd
P
Ph2
12
(12)
11
(11)
A rgoGel
resin
N
n
C l–
Cl
Ph2 H
P
H
Ru
N
P
PPh3
Ph22 PPh
Ph
3
15
(15)
Platinum Metals Rev., 2008, 52, (4)
Ar goGel
resin
14
(14)
Cl
PCy3
Ru
Cl
Ph
PCy3
16
(16)
219
ported octahedral Ru(II) diphosphine complexes
14 and 15 as brown and yellow beads respectively
(23). Both compounds were shown to hydrogenate supercritical carbon dioxide in the
presence of dimethylamine (HN(CH3)2) to give
dimethylformamide (DMF, HCON(CH3)2). The
catalysts could be reused up to four times, after
decantation and drying under vacuum, with some
loss in catalytic activity. Polymer-based phosphine
resins have recently been shown to act as scavengers for removal of Grubbs’ catalyst, 16, from
reaction mixtures, and could be separated by simple filtration delivering > 95% Ru-free reaction
products (24).
Conclusions and Future Work
The PBMC approach continues to be an attractive, yet simple, preparative method for accessing
new trivalent phosphorus(III) ligands. Phosphines
offer important insights into how structural ligand
modifications can be made, allowing different ligating modes to be adopted at pgm centres.
Furthermore, careful incorporation of highly polar
functional groups can lead to diverse solid-state
structures. The ease of using the PBMC approach
to target late transition metal-based catalysts, with
recyclable properties, offers practical alternatives
in the field of homogeneous catalysis.
Unpublished recent work from our group has
taken us back to some earlier studies reviewed in
Platinum Metals Review (25). We are using
tetrakis(hydroxymethyl)phosphonium chloride
(THPC), itself a precursor used to prepare
tris(hydroxymethyl)phosphine (THP), as a starting
reagent for the preparation of neutral and cationic
phosphorus-containing ligands. The pgm coordination chemistry of these new ligands has provided
us with some interesting results that will be published shortly (26).
Acknowledgements
The author would like to acknowledge those
involved in supporting our research activities,
especially Johnson Matthey PLC. Many thanks to
all group members, past and present, who have
made valuable contributions in the areas of pgm
chemistry with phosphorus-based ligands, catalysis
and supramolecular chemistry.
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The Author
Martin Smith was born in Royston, Hertfordshire, U.K., and grew up in
the neighbouring village of Melbourn. He was awarded a B.Sc. in
Chemistry at the University of Warwick, U.K., and completed his Ph.D.
at Bristol University in the group of Professor Paul Pringle. After
postdoctoral positions and a Royal Society Fellowship with Professors
Tony Deeming (University College London), Brian James (University of
British Columbia, Canada) and Derek Woollins (Loughborough
University) he took up a Lectureship at Loughborough University in
1997. He was promoted to Senior Lecturer in 2008. His research
interests are focused on pgm phosphine complexes and their applications in catalysis.
Platinum Metals Rev., 2008, 52, (4)
221
DOI: 10.1595/147106708X363437
EuropaCat VIII: “From Theory to
Industrial Practice”
PLATINUM GROUP METALS RETAIN FUNDAMENTAL ROLE IN CATALYSIS
Reviewed by Emma Schofield*, Nadia Acerbi and Cristian Spadoni
Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.; *E-mail: [email protected]
This biennial European Federation of Catalysis
Societies (EFCATS) conference took place on the
26th to 31st August 2007, in the town of Turku on
the southwestern coast of Finland, and was hosted
by the Nordic Catalysis Society (1). It was attended by 1350 scientists from Asia, the U.S.A. and
Europe, of whom 65% were men, with an industrial representation of 40%. The oral presentations
included seven plenary lectures, one or more
keynote lectures for each session, 180 oral presentations in four parallel sessions and 750 posters.
The significance of this conference was highlighted by the fact that there were up to ninety
submissions for a session from which only ten presentations could be selected. Presentations were
divided into eighteen topic areas:
– Catalysis from first principles
– Nanotechnology in catalysis, novel catalytic
materials
– Surface science in catalysis
– New experimental approaches and characterisation under reaction conditions (combinatorial
methods included)
– Catalysis for pharma and fine chemistry (homoand heterogeneous catalysis)
– Catalysis by enzymes
– Polymerisation
– Electro-catalysis and catalysis related to fuel
cells
– Catalysis in oil refining
– Natural gas conversion (GTL, MTO, methanol,
etc.)
– The Hydrogen Society (hydrogen production
and storage)
– Catalysis in the conversion of renewable
resources (biofuels, catalysis for sustainable
developments)
– Catalysis for pollution control (stationary)
Platinum Metals Rev., 2008, 52, (4), 222–228
– Catalysis for pollution control (mobile)
– Catalysis for bulk and specialty chemicals
– Catalytic reaction engineering (novel reactor
systems and novel reaction media included)
– Photocatalysis
– Catalyst deactivation, regeneration and recycling
There was also a workshop entitled “Towards
100% Selectivity in Catalytic Oxidation over
Nanostructured Metal Oxides” (VIII European
Workshop on Selective Oxidation ISO 2007, hosted by EuropaCat VIII).
Platinum group metals (pgms) featured in most
of these sessions, and retain their pivotal roles in
fuel cell catalysis, automotive applications, surface
science and photocatalysis.
The Berzelius Lecture
Among the plenary lectures of the conference
was the Berzelius Lecture, resurrected by the
EuropaCat committee in honour of the Swedish
scientist who, in a report in 1836, highlighted the
“significance of reactions which take place in the
presence of some substance which remains unaffected” (2). This year, this prestigious lecture was
given by Nobel Laureate R. H. Grubbs (California
Institute of Technology, U.S.A.) after whom is
named the homogeneous Grubbs’ catalyst. This
catalyst is an efficient, selective catalyst for olefin
metathesis which works under mild reaction conditions that tolerate the presence of a range of
other functionalities. More than fifty Grubbs’ catalysts have been synthesised. Grubbs
demonstrated that, by tuning the N-heterocyclic
carbene ligands on the ruthenium centre, the catalyst can be made more reactive or more stable,
water soluble or enantioselective. Recent work has
focused on increasing the barrier to decomposition
by hindering the ligand rotation which is the initial
222
step in this pathway. The consequences of modifying the catalyst ligands by a single methyl group
were further illustrated in ethanolysis, in which
this structural refinement resulted in a decrease in
reaction times from 20 h to 1 h, maintaining the
high selectivity. For larger scale applications, a
Grubbs’ catalyst is being explored for conversion
of seed oils – corn and soy bean – into value added
chemicals. In these clean, solvent-free reactions,
the functionalities already present in the oils are
retained at high turnover numbers.
Catalysis from First Principles
J. A. van Bokhoven (ETH Zurich, Switzerland)
gave a well-attended and inspirational talk on the
ways in which oxide supported nanoparticles of
gold are different from bulk metal or crystals. The
catalysts discussed were prepared by base deposition precipitation from hydrogen tetrachloroaurate
(HAuCl4) on a range of supports: alumina (Al2O3),
silica (SiO2), ceria (CeO2), titania (TiO2), zirconia
(ZrO2) or niobium oxide (Nb2O5). Independent of
the support, as the size of Au particles decreases,
melting point, coordination number and bond
lengths to adjacent atoms all decrease. The reason
is that smaller particles have a different electronic
structure. This was explained in terms of the fact
that the d-band narrows and shifts up in energy
towards the Fermi level as particle size decreases.
The consequence is that the particles are catalytically reactive where the bulk metal is not. Using
X-ray techniques – X-ray absorption near edge
structure (XANES), extended X-ray absorption
fine structure (EXAFS) – and in particular by the
use of hard X-rays for high resolution, van
Bokhoven showed that nanosized Au interacts
with H2 and O2 and demonstrated that, for the
hydrogenation of cinamaldehyde, smaller particles
exhibit a higher selectivity. The issue of support
effects was raised in the questions; the point was
reiterated that, while support effects are clearly
important in catalysis on Au, they did not influence the electronic particle properties under
discussion.
Novel phenomena related to Au clusters
deposited on ultra-thin oxide films were discussed
by G. Pacchioni (Università degli Studi di Milano-
Platinum Metals Rev., 2008, 52, (4)
Bicocca, Italy). He showed by means of density
functional theory (DFT) calculations how oxide
thin films may exhibit special properties which differ from the bulk oxide. He considered a system in
which a thin layer of magnesium oxide (MgO) is
grown on a metal, in this case silver or molybdenum. Subsequently Au particles are deposited on
the metal oxide support. The formation of a
metal/oxide interface can change the chemical
properties of the oxide support and the system
work function. When the supporting metal is Mo,
what results is the charging of the supported metal
atoms and clusters by direct tunneling of electrons
from the metal substrate to the supported metal;
this is not observed when Ag is used. The reason
for this electronic behaviour is that the Fermi level
of Ag is lower in energy than the Au 6s orbital, so
spontaneous electron tunneling is not allowed; in
contrast the Fermi level of Mo lies at higher
energy than the Au 6s.
This fundamental approach to the behaviour of
catalytic metal particles was taken further by J. K.
Nørskov (Technical University of Denmark) who
discussed the reactivity of catalysts in terms of the
geometrical and electronic structure of metal
nanoparticles. Having discussed the correlations
between the energy of d-states and the reactivity of
a catalyst, he illustrated the practical applications
of the theoretical principles in the synthesis of
ammonia on 11% Ru on a MgAl spinel. On the Ru
nanoparticle surface in this catalyst there are closepacked regions, on which there is a large barrier to
dissociation, and steps, where the barrier is much
lower and where the catalysis occurs. The question
is then how many step sites there are on the
nanoparticles, which can be modelled from transmission electron microscope (TEM) images.
Around 2–3 nm, the required steps are no longer
possible, hence the optimal nanoparticle size is >
3 nm. Although these are simple examples, they
serve to illustrate the enormous potential of computational chemistry in predicting useful catalyst
structures.
Surface Science
Investigating the surface science of platinum
and palladium, T. Visart de Bocarmé (Université
223
Libre de Bruxelles, Belgium) illustrated the usefulness of field ion microscopy to elucidate the active
sites and chemical species relevant to a catalytic
reaction. Observing the reaction between H2 and
NO on a Pt tip showed that an oscillatory reaction
occurs with local oxide reduction by H2 during the
oscillating cycles. The reaction occurs on the kink
surfaces of the (012) planes where there are [001]
zones. For Pd in contrast, there are no plane-specific effects and hysteresis rather than oscillation is
observed; here reduction of oxides is only possible
at high pressures of H2.
Extending the scope of his studies to all the
pgms, M. Johansson (Technical University of
Denmark) measured splitting coefficients and
desorption rates in the hydrogen–deuterium
exchange reaction with and without added carbon
monoxide on a range of pgms in 1 bar H2 at
temperatures between 40 and 200ºC. Surprisingly,
in the absence of CO, Ru and Rh proved to have
the highest sticking probabilities: the order followed: Ru > Rh >> Pd ~ Pt > Ir. The addition of
CO slows the reaction for all the metals, in particular Pt and iridium.
Pd was the focus of the talk by W. T. Tysoe
(University of Wisconsin-Milwaukee, U.S.A.). He
used deuterium-labelling to investigate the reaction
mechanism of the industrially significant vinyl
acetate monomer (VAM) reaction on, in this case,
a Pd(111) surface, in which ethene reacts oxidatively with acetic acid. Using an elegant
combination of variable temperature infrared (IR)
and temperature-programmed desorption (TPD)
spectroscopy, he showed that changing the
labelled ethenes – CHD=CHD or CH2=CD2 –
gave different rates of reaction. The conclusion
that the reaction on Pd proceeds via the Samanos
pathway (3) was substantiated by DFT, which predicts that the Samanos pathway is energetically
more favourable. In the subsequent discussion the
possibility was raised that the pathway may be different on a PdAu alloy.
S. Schauermann (Fritz-Haber-Institut der MaxPlanck-Gesellschaft, Germany) demonstrated the
active role played by the support iron oxide
(Fe2O3) in the decomposition of methanol. In a
model system in which crystalline particles of Pd
Platinum Metals Rev., 2008, 52, (4)
were prepared on an Fe2O3 film deposited on a
Pt(111) surface, at T > 450 K she showed that O2
was chemisorbed on metallic Pd. At T > 500 K,
layers of PdO formed at the particle–support interface, leading to the coexistence of PdO and Pd
metal. At T > 600 K, there was nearly complete
oxidation of the particle. The consequences of the
decomposition of MeOH are that a reservoir of
predissociated methoxy species build up on the
Fe2O3 support which spill over onto the Pd particles in order to react. On the theme of reactions of
MeOH, R. Blume (Fritz-Haber-Institut der MaxPlanck-Gesellschaft, Germany) showed that in the
oxidation of MeOH to formaldehyde on oxidic Ru
surfaces, different precatalysts evolve into the
same catalytically active surface. The amount of
transition surface oxide in the first few layers
proved to be the parameter which determines
which catalytic pathway is followed rather than the
amount of RuO2.
Alcohols also featured in the investigation of N.
Bion (Université de Poitiers, France) into the
steam
reforming
of
bioethanol
over
Rh/MgAl2O4/Al2O3 to generate H2. In crude
bioethanol there are a range of impurities which
deactivate this reaction. Each impurity was tested
individually and it was shown that there is a strong
poisoning effect of acetic acid – although there are
only low levels of acetic acid in bioethanol – and
no inhibition by diethylamine. Of a series of alcohols, the order of poisoning was: branched > linear
> other functional groups. This was thought to be
due partly to coke deposition and partly influenced
by the hydrophobicity of the alcohol, where the C4
and C5 alcohols hinder water activation. Following
the ethanol theme, W. Shen (Dalian Institute of
Chemical Physics, Chinese Academy of Sciences)
proposed an Ir/CeO2 catalyst for steam reforming
of ethanol. He showed that, while there was only
limited sintering of Ir during the 60 h test reaction,
there was significant growth and morphological
changes of the ceria particles, although this did not
influence the catalytic activity noticeably.
New Experimental Approaches
In situ techniques, which can be used to study
the structural modification of catalysts under real-
224
life reaction conditions, are of critical importance
to any scientist who is trying to understand how a
catalyst really behaves. J.-D. Grunwaldt (ETH
Zurich, Switzerland) presented 2D mapping of
supported pgm catalysts under operational conditions in order to investigate the variation of the
catalyst structure that can occur inside a catalytic
reactor as a result of prominent temperature or
concentration gradients. The catalytic systems
studied were alumina supported pgms (Rh/Al2O3,
Pt-Rh/Al2O3, Pt/Al2O3, Pt-Ru/Al2O3, Pd/Al2O3)
prepared by flame-spray pyrolysis and the reaction
studied was the total oxidation of methane. X-Ray
absorption spectroscopy (XAS), recorded with a
micro-focused beam scanning over the sample
coupled with a 2D-area detector, is particularly
effective for in situ studies since it requires shorter
acquisition times. The temperature profile was
analysed using an IR thermography camera and
the catalytic performance by means of mass spectrometry. It was shown that the structure of a
catalyst during partial oxidation of methane varies
strongly along the axial coordinate of a tubular
catalytic microreactor. There are considerable
structural differences between the pgm particles of
less than 100 μm diameter, and a strong dependence on the reaction conditions (temperature,
space velocity). This talk highlighted the importance of 2D-spectroscopic studies under
operational reaction conditions.
A. Tompos (Chemical Research Center,
Institute of Surface Chemistry and Catalysis,
Hungarian Academy of Sciences) used catalysts
combinatorially designed for methane total oxidation in order to understand the role of Pt and Au
on the performance of trimetallic Pt-Pd-Au/CeO2
catalysts. Ceria was obtained by the urea precipitation route and subsequently impregnated with the
three metals. By X-ray photoelectron spectroscopy,
in situ Fourier transform infrared (FTIR) spectroscopy, TPD of H2 and CO chemisorption
measurements, direct evidence was found for
alloying of Pt with Pd. The conclusion was that the
improved catalytic properties of multimetallic PtPd-Au/CeO2 catalysts over the monometallic Pd
analogues are due to: (a) the increase of the
number of Pd(0)–PdO dual-type active sites,
Platinum Metals Rev., 2008, 52, (4)
(b) stronger methane adsorption at the Pd(0)–PdO
boundary, (c) a higher accessible metallic area in
the working catalyst, (d) suppression of the reduction of Ce(IV), and (e) suppression of the
concentration of ionic Pd(II).
Novel Catalytic Materials
The pgms are the first port of call for scientists
in search of new catalytic materials. Pd featured in
the talk by G. L. Chiarello (Università degli Studi
di Milano, Italy). He compared 0.5% Pd/LaCoO3
catalysts made by flame-spray pyrolysis with more
conventional catalysts prepared by impregnation
in the reaction in which small amounts of H2 in
exhaust gases are used to reduce NO. In the
flame-made catalyst, the Pd(II) partially replaces
Co in the perovskite structure. When this catalyst
is calcined at 800ºC and reduced at 300ºC in 5%
H2/He, Pd segregates to the catalyst surface. In
contrast, reduction at 600ºC leads to the formation
of a PdCo alloy. A further feature of the flamemade catalyst is that at temperatures over 500ºC,
EXAFS evidence suggested that the Pd redissolves
in the perovskite framework instead of sintering,
putting this in the class of so-called ‘intelligent
catalysts’ which redisperse following sintering. The
flame-based preparation route gave a clear advantage in catalyst performance over the impregnation
method; the catalyst yielded 100% conversion at
160ºC along with 78% selectivity to nitrogen and
after 100 h there was no deactivation of the flamemade catalyst.
Encapsulated pgm nanoparticles are the novel
approach to preventing sintering described by M.
Paul (Max-Planck-Institute for Coal Research,
Germany). He proposed encapsulating Au or Pt
nanoparticles in hollow metal oxide spheres. In
this way the nanoparticles are physically separate
and sintering is prevented at high temperatures. By
this method a colloidal nanoparticle is encapsulated in a silica shell, which is then coated with
zirconia or titania and calcined at 900ºC.
Subsequently the silica core is leached out by treatment with sodium hydroxide. TEM images
showed the effective encapsulation. Using the CO
oxidation reaction, it was shown that hollow
sphere encapsulation does stabilise the catalyst
225
against sintering while causing no mass-transfer
limitation and thus retaining catalytic activity.
As a catalytic element, Au has proved a particularly popular subject of study since Haruta’s work
in the 1980s (4). In this meeting, S. Carrettin
(Instituto de Tecnología Química, CSIC, Spain)
gave a pioneering example of a heterogeneous Au
catalyst used for a carbon–carbon bond formation,
namely the isomerisation of ω-alkynylfurans to
phenols. The 1.8% Au on ceria catalyst was prepared using HAuCl4 and nanocrystalline ceria. The
nanocrystalline support seems to stabilise the
cationic species Au(I) and Au(III): the presence of
these species on the surface was established by
observing CO probe molecules by FTIR spectroscopy. The hypothesis that the Au cationic
species is the active site was challenged during the
discussion, and the question remained as to
whether FTIR is a sufficiently sensitive technique
to allow Au(I) and Au(III) differentiation.
Well known in the field of Au catalysis, G. J.
Hutchings (Cardiff University, U.K.) presented a
new synthetic approach to supports for highly
active oxidation catalysts. Au supported on ceria
prepared using supercritical antisolvent (scCO2)
precipitation was demonstrably more active and
more stable for CO oxidation than comparable
nanoparticles supported on conventional ceria
derived from the direct calcination of cerium(III)
acetylacetonate. In search of new industrial uses
for Au catalysts J. McPherson (Project AuTEK,
South Africa) deposited Au on hopcalite with the
aim of improving the stability of this filter material to water. Despite extremely efficient deposition
of Au, Au/ZnO and Au/TiO2 proved more active
for aspirator applications.
Automotive Catalysis
As ever, pgms played a starring role in the section on automotive catalysis. In the section on
NOx traps E. C. Corbos (Université de Poitiers,
France) elegantly illustrated the redispersion of Pt
on ceria-containing supports at temperatures
greater than 800ºC in an oxidising atmosphere.
The techniques used were in situ time-resolved
turbo XAS in fluorescence mode and in situ TEM.
In a cycling regime of 3% H2/He (60 s) followed
Platinum Metals Rev., 2008, 52, (4)
by 20% O2/He (60 s), the particles which start at
7 nm decrease in size to 5 nm within 30 s and to
3 nm within 1000 s. The hypothesis was that the
oxidised atoms migrate. In the discussion the
question was raised concerning the influence of
water on these process, which is yet to be studied.
H. Grönbeck (Chalmers University of
Technology, Sweden) approached NOx storage
from a computational perspective, using super-cell
calculations to examine the adsorption of NO2 on
layers of barium oxide(100) on Pt(100). The
adsorption energy of BaO (Ea = 1.04) is enhanced
by a factor of 2 (Ea = 2.38) when two layers of
BaO are arranged on the Pt surface and there is a
noticeable effect even up to 5 layers, 16 Å, of BaO
between the Pt and the NO2. It was proposed that
a similarly substantial effect would be observed on
Pt supported MgO(100) (Ea = 1.65) with charging
of the NO2 molecule induced by the Pt–MgO
interaction.
The theme of the talk by R. Burch (University
of Belfast, Northern Ireland) was the importance
of scientific rigour, in particular in not theorising
beyond the available data. This is particularly
important in studying non-steady state processes.
In order to study NOx storage on 1% Pt/17.5%
Ba/γ-alumina, Burch uses fast transient kinetics
apparatus with very short residence times and a full
gas mixture. The conclusion was that NH3 is only
observed in large quantities over a Pt catalyst when
H2 alone is used as the reductant. With the typical
3:1 CO:H2 mixture, CO inhibits the formation
(release) of NH3.
Among the talks devoted to catalytic combustion, A. Baylet (Université de Poitiers, France) and
P. Gélin (Université de Lyon, France) shared a
theme of catalytic combustion of natural gas over
supported PdO. Since metallic Pd is much less
reactive than its oxide, and reoxidation of Pd may
be the rate limiting step in the reaction, different
approaches were taken to increase the PdO:Pd
ratio. A. Baylet doped highly thermally stable hexaaluminate supports (La0.2Sr0.3Ba0.5)(MnAl11)O19 with
1% Pd; the most effective catalyst proved to be a
hexaaluminate/alumina mixture. The approach of
P. Gélin was to vary the support in order to
increase the PdO–Pd transition temperature,
226
achieving the highest activity on Pd/YSZ in the
absence of sulfur. Only Pd/Al2O3 was not
poisoned by sulfur.
The theme of catalytic combustion was continued by A. de Lucas-Consuegra (Universidad de
Castilla-La Mancha, Spain) who discussed the use
of solid electrolytes to make conducting electroactive catalyst supports for use in the catalytic
combustion of hydrocarbons, exemplified by
propane. Promoting 1% Pt/β-Al2O3 with potassium ions gives a catalyst that operates, both in
near-stoichiometric and O2 rich conditions, at
lower temperatures – around 200ºC – well within
the 190–310ºC working exhaust temperature.
Fuel Cells
For some time a lot of scientific effort has been
devoted to decreasing the amount of pgm required
for efficient operation of a fuel cell. M. Tada
(University of Tokyo, Japan) used an impressive
range of in situ XAS techniques to study the mechanism of the O2 reduction reaction at the cathode
on a Pt/C catalyst under realistic operating conditions. Two in situ time-resolved techniques were
used: time-gated EXAFS (TG-EXAFS), with a
time resolution of 1 s and in situ time-resolved
energy-dispersive EXAFS (DXANES), with a
resolution of 4 ms. Having estimated all kinetic
parameters for the reaction, she concluded that
there are eight elementary steps involved, and
there is a significant time lag between electron
transfer and structural changes in the Pt catalyst.
Since the Pt–Pt bond dissociation rate and the
PtO bond formation rate constants are similar, it
was shown that at higher potentials than the open
circuit voltage oxygen atoms break in to the subsurface of the Pt nanoparticles.
N. Tsiouvaras (Universidad de la Laguna,
Spain) gave a controversial presentation on ternary
catalysts for direct methanol fuel cells in which Mo
had been introduced to PtRu/C at loadings of
between 2 and 12 wt.% for an overall 30% metal
loading. Pt crystallite sizes of 2–5 nm were
observed; there was no evidence of alloying.
Although the catalyst displayed high metal losses
on electrochemical cycling – mostly of Mo – the
CO stripping potentials were lower than the com-
Platinum Metals Rev., 2008, 52, (4)
mercial 30% PtRu/C standard. Using differential
electrochemical mass spectrometry, the gases
produced during electrochemical processes were
analysed demonstrating that the onset of CO2
production was at lower potentials than observed
for commercial catalysts. Similarly, by carrying out
in situ FTIR on the electrochemical cell, it
appeared that qualitatively a small quantity of CO
poisoned the ternary catalyst surface. Finally, tests
for activity in MeOH oxidation again gave higher
current densities than the commercial standard.
Photocatalysis
A. Kudo (Tokyo University of Science, Japan)
demonstrated an exciting system for solar H2 production from water. Ru/SiTiO3 doped with Rh
was the catalyst for H2 generation; this proved
better than the Pt analogue because the presence
of Ru effectively suppresses the back reaction. By
preparing the catalyst by a hydrothermal rather
than solid state route, an improvement in quantum
yield to 3.9% from 0.3% resulted. The improvement was thought to be due to the better
crystallinity, smaller particle size and decrease in
grain boundaries in the hydrothermally prepared
catalyst, providing fewer sites where recombination could occur. The optimal system combined
Ru/SiTiO3:Rh for H2 generation with BiVO4 for
O2 generation, using Fe(III) as the couple mediator, and gave a system responsive up to 520 nm.
Selective Oxidation
A. Pashkova (DECHEMA, Germany)
presented a new approach for the synthesis of
hydrogen peroxide directly from H2 and O2.
Single channel asymmetric membranes were used
as the support for the active Pd or Pd-Ag alloy
species. The selectivity for H2O2 could be
increased from 20% to 80% by changing the concentration profiles of O2 and H2 from
countercurrent to equicurrent profiles.
The selective generation of propylene oxide by
epoxidation of propylene was the subject of a
paper by N. Mimura (Research Institute for
Innovation in Sustainable Chemistry, Japan). The
epoxidation was carried out using a mixture of H2
and O2 over titania supported Au nanoparticles
227
prepared
by
deposition
precipitation.
Characterisation showed that the nanoparticles
had deposited only on the four-coordinate titanium sites. The problem of the explosion limit was
solved by feeding in H2 and O2 in two separate
streams and using a membrane in the catalyst area.
Similarly good performances were obtained with
Au on titanium silicalite-1 (TS-1) and with Mo
oxide on silica for epoxidation by molecular O2.
Conclusion
EuropaCat VIII proved to be a key conference
for any researcher studying the behaviour and
characterisation of catalysts. An impressive selection of oral and written presentations generated
what was certainly high quality if occasionally
somewhat heated discussion both in and out of the
conference venue. The high industrial representa-
tion attested to the significance of the conference
to the wider commercial world. It was clear that
pgms retain their fundamental role in many
branches of catalysis and, despite or perhaps as a
result of all efforts at substitution and thrifting, will
continue to be the focus of considerable catalyst
research activity for the foreseeable future.
EuropaCat IX: “Catalysis for a Sustainable
World” will take place in Salamanca, Spain, from
30th August to 4th September 2009 (5).
References
1
2
3
4
5
EuropaCat VIII: http://www.europacat.org/
Berzelius, Ann. Chim. Phys. (Paris), 1836, 61, 146
B. Samanos, P. Boutry and R. Montarnal, J. Catal.,
1971, 23, (1), 19
M. Haruta, T. Kobayashi, H. Sano and N. Yamada,
Chem. Lett., 1987, 16, (2), 405
EuropaCat IX: http://www.europacat2009.eu/
The Reviewers
After her Ph.D. in Coordination
Chemistry in Basel, Switzerland (1999),
Emma Schofield spend two years as a
post-doctoral researcher in Strasbourg,
France, before taking up a Lectureship in
Inorganic Chemistry at Trinity College in
Dublin, Ireland. In 2004 she moved to
Johnson Matthey in the U.K. where she
specialises in developing new synthetic routes to heterogeneous
catalysts.
After specialising in heterogeneous
catalysis applied to environmental
technology at the Universidad
Complutense de Madrid, Spain, and
graduating from the Università di
Urbino, Italy, Nadia Acerbi started her
Ph.D. with Johnson Matthey in the
framework of the Marie Curie Actions
and in collaboration with the University of Oxford, U.K. Her
research is focused on ‘Novel Nano-Coated Catalysts for
Selective Oxidation of Hydrocarbons’.
Cristian Spadoni graduated from the
Facoltà di Chimica Industriale, Università
di Bologna, Italy, with a specialisation in
heterogeneous catalysis. He started his
Ph.D. in Chemical Engineering with
Johnson Matthey in the framework of the
Marie Curie Actions and in collaboration
with the University of Bath, U.K. His
research has been focused on ‘Direct
Synthesis of Hydrogen Peroxide from Oxygen and Hydrogen’.
Platinum Metals Rev., 2008, 52, (4)
228
DOI: 10.1595/147106708X364922
“Catalysis for Renewables: From
Feedstock to Energy Production”
EDITED BY GABRIELE CENTI (University of Messina, Italy) and RUTGER A. VAN SANTEN (Eindhoven University of Technology,
The Netherlands), Wiley-VCH, Weinheim, Germany, 2007, 448 pages, ISBN 978-3-527-31788-2, £105.00, €141.80, U.S.$200.00
Reviewed by John Birtill
15 Portman Rise, Guisborough, Cleveland TS14 7LW, U.K.; E-mail: [email protected]
The drive for renewable feedstocks and fuels is
a hot topic for scientists and governments, and
catalysis is a key enabling technology for the
development of new and improved processes.
Hence, the appearance of this book is well timed. I
am not sure about the publisher’s claim that “this
will be a white book in the field”. The sixteen
chapters are mostly reviews, and some of them
have overlapping content. As with any type of
boom, this research field is prone to exaggerated
claims and false trails. Competition between food
and biofeedstocks is likely in due course to discourage the use of food crops, but agricultural
(lignocellulosic) waste products and targeted crops
from marginal land have long-term potential.
The content originated in a workshop,
“Catalysis for Renewables”, held in the
Netherlands in 2006, and organised within the EU
sponsored ‘IDECAT’ (Integrated Design of
Catalytic Nanomaterials for a Sustainable
Production) framework (1). The editors of the
book were members of the Organising Committee.
The aim was to define “new directions and opportunities for catalytic research in this field by
integrating industrial, governmental and academic
points of view”. The authors are mostly academic
and government scientists from the Netherlands
and Italy, with a few more from France and
Finland. There are very few industrial scientists.
Hence, although the subject matter is of global
geopolitical and industrial significance, the content
reflects the views of attendees at this regional,
academic workshop. However, the reviews cover a
wide range of literature, and so the book serves as
a useful source of information.
Each chapter clearly stands alone as the work of
its authors, suggesting a light editorial touch. Most
Platinum Metals Rev., 2008, 52, (4), 229–230
of the reviews are informative, and a few are excellent. I liked the overall perspective on renewable
catalytic technologies in the early chapters and the
roadmap in the final chapter. Various controversial
points are well described, regarding the magnitude
of environmental challenges and the effectiveness
of proposed solutions. However, the lists of academic studies of catalytic reactions in chapters on
chemical transformations are not very helpful
without some critical appraisal of their true potential for application (cost, robustness, effectiveness).
The early chapters cover the biomass conversion
chain, from the biorefinery to fuels and chemical
products. The ordering of later chapters seems
more random. Chapter 8, which describes combustion modelling, appears to be in the wrong
book. There are further chapters on bioethanol
production and upgrading, the conversion of
glycerol to diesel components, other chemicals and
syngas (carbon monoxide and hydrogen), and the
methodology of cascade catalysis. The chapters on
hydrogen production and fuel cells, and the
techno-commercial and environmental case for
hydrogen in transportation are loosely linked to the
title theme, but are relevant for strategic reasons.
The production of hydrogen by solar photocatalysis is the biggest challenge for the future.
In general, there is little novel catalysis in this
book. The production chain from the biorefinery
is based on catalytic unit operations familiar to
the chemical industry. Hence, processes such as
reforming, hydrogenation, oxidation, hydrolysis
and etherification appear throughout the book.
New catalytic requirements do appear, for
example, in the selective deoxygenation of certain intermediates. There is an interesting
roadmap in the final chapter for priorities in
229
catalysis research into renewable raw materials
and sources of energy.
Not surprisingly, there are many passing references throughout the book to supported and/or
bifunctional platinum group metal catalysts, for
example hydrogenation (palladium, platinum,
ruthenium, rhodium, iridium), hydrogenolysis
(Pd), dehydrogenation (Pd), oxidation (Pt, Pd),
homogeneous telomerisation (Pd), homogeneous
hydrogenation (Rh), steam reforming (Pt), aqueous
reforming (Ru, Pt, Pd) and electrocatalysis (Pt).
However, many of these references have not been
included in the index. The practical conversion of
biofeedstocks is certain to place new demands on
the robustness of catalysts, but this aspect is
hardly mentioned by the mainly academic authors.
A chapter on new challenges for catalyst design
might have been useful, but I suppose that no-one
talked about this at the IDECAT workshop.
Besides the lack of industrial experience of bioprocessing, other notable omissions include the
potential use of marine harvests and municipal
waste.
In conclusion, this book will be useful to anyone who wants an academic, strategic perspective
on the potential contributions from various catalytic technologies to this field of research. The
lack of industrial perspective is its most serious
weakness. The price will limit its purchase mainly
to libraries. It will be read by academic and industrial scientists, research students seeking a wider
perspective, and those concerned with science
policy. For instance, the issues of food competition and poor overall effectiveness attached to use
of some food crops as industrial feedstocks are
well explained, and it is surprising that these issues
have only recently become politically controversial.
Anyone interested in detailed catalytic science will
find texts dedicated to the respective catalytic technologies to be more useful; for a general source,
see for example Reference (2).
References
1
2
IDECAT Conference Series, Catalysis for
Renewables Conference:
http://idecat.unime.it/index.php?pag=CatForRen
C. H. Bartholomew and R. J. Farrauto,
“Fundamentals of Industrial Catalytic Processes”,
2nd Edn., Wiley-Interscience, Weinheim, Germany,
2006
The Reviewer
John Birtill is a consultant in industrial
catalytic technology, an Honorary Research
Fellow at the University of Glasgow, U.K.,
and Secretary of the Royal Society of
Chemistry Applied Catalysis Group. See his
website at: www.catalyst-decay.com for
more information.
Platinum Metals Rev., 2008, 52, (4)
230
DOI: 10.1595/147106708X362735
Platinum Group Metals Patent Analysis
and Mapping
A REVIEW OF PATENTING TRENDS AND IDENTIFICATION OF EMERGING TECHNOLOGIES
By Richard Seymour
Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.; E-mail: [email protected]
The patent literature contains a wealth of detailed information about existing and new uses
for the platinum group metals (pgms). While excellent searching tools have existed for many
years for identifying patents relating to specific topics, it is only relatively recently that it
has been feasible to map the complete archive of patent literature to identify important
trends relating to potential new applications. This paper summarises the results of such an
exercise for the pgms carried out in early 2008 and shows that one such ‘hot spot’ relates to
organic light emitting diodes (OLEDs).
Previous articles in this Journal have described
the importance of patents as a key source of technical and commercial intelligence (1, 2). The use of
patent mapping to visualise large sets of patent data
and to identify trends contained within that data has
also been demonstrated (2). The present paper further develops these themes by examining the patent
literature on pgms published since 1983, in particular that on the minor metals iridium and ruthenium.
Searching – What and Where?
I will begin by thinking about search strategy. In
this case, the initial objective is to create a large set
of patents relating to the pgms, which will later be
analysed and refined. The choice of keywords is
therefore straightforward: platinum, palladium,
rhodium, iridium, osmium and ruthenium. In the
patent literature it is unlikely that the names of
these metals would be used in other contexts.
However, this might be a difficult problem if we
were searching the news or business press, where
the names of the pgms are associated with many
brand names – for example there would probably
be many hits on topics such as platinum credit
cards or iridium satellite communication systems,
and strategies for removing such material would
need to be found.
Perhaps a more important question to ask is
which patent collections to use to search for these
words? The software package used at the Johnson
Platinum Metals Rev., 2008, 52, (4), 231–240
Matthey Technology Centre is Aureka® (a product
available from Thomson Reuters) (3), which
includes patent data sets from the Patent
Cooperation Treaty (PCT) and European Patent
offices, plus a range of national patent collections
including those of the U.S.A., Japan, the U.K.,
France and Germany. With the exception of Japan,
these collections contain full-text patent documents, available either as PDF or HTML files. In
the case of Japanese patents, a text version of the
English-language title, abstract and other front
page details is available, together with a PDF file of
the full specification in Japanese.
It must be borne in mind that using the French
and German collections would require us to search
in French or German respectively, and of course
the results obtained would also be in French or
German. The patent collections of other countries,
for example China and India, are not currently
available in Aureka. However at this stage we are
looking for the big picture. The detail can follow
later if necessary, for example by adding Chinese
patent documents retrieved from other patent
databases.
We also need to think about where in the
patent document we might wish to search for
information on pgms. This is an important question and to understand the various possibilities
and their implications we first need to think about
the structure of a typical patent:
231
– Title: often deliberately rather vague and nonspecific.
– Abstract: a short summary of the invention, in
perhaps 100 to 200 words.
– Claims: the claims of a patent govern its legal
effect, that is, the areas of technology that are to
be monopolised. Generally it can be said that a
feature is not protected unless that feature is
claimed or covered by the general language in
the claims. So these are key – get the claims
wrong and your invention may be seriously
compromised.
Then, depending on the particular country, there
may also be sections on:
– Background: provides details on the context of
the invention, current technology, and why
existing solutions may be inadequate.
– Description: a detailed description of the invention and possible variants thereof.
– Examples: worked examples, covering aspects
such as how the invention is made. Scientists
sometimes wrongly concentrate on the examples just as they would read the experimental
sections of scientific papers.
Now let us suppose we are searching for patents
in which a new pgm chemical or material is disclosed, or in which the use of a pgm is a key part of
the invention. In this case restricting the search to
terms in the title or abstract, and possibly also the
claims, will be adequate. Clearly if the word ‘platinum’ appears in any of these sections then it is
likely to be a very important part of the invention.
But what about the case when the name of the
pgm appears somewhere in the rest of the patent,
but not in the title, abstract or claims? Can these
patents safely be ignored? An example of such
patents might be the use of a standard palladium
on carbon hydrogenation catalyst in a multi-stage
organic synthesis route. The novelty is in the endproduct, not the catalyst used, and therefore the
term ‘palladium’ is unlikely to occur in the title,
abstract or claims. However it may well come up in
the examples. While we can probably ignore such
patents for the purpose of identifying key new
application areas, important information may
nevertheless be obtained from them. For example,
they may provide valuable intelligence on sales
Platinum Metals Rev., 2008, 52, (4)
opportunities for suppliers of catalysts, the customer being the owner of the patent.
Table I illustrates the wide variation in the number of retrieved patents obtained according to
where in the patent the search is performed. The
table clearly shows that choosing which part of the
patent document to search is critical. If we search
in the patent title, abstract and claims then we
retrieve over five times as many patents as exactly
the same search restricted to just title and abstract.
If we search in the full text of the patent then we
retrieve five times as many again.
Table I
Searches on the Term ‘Platinum’ Conducted in
the U.S. Granted Patent Collection, for Patents
Published between 1st January 2001 and 31st
December 2007
Criteria
Number of ‘hits’
‘Platinum’ in the patent
title or abstract
1611
‘Platinum’ in the patent
title, abstract or claims
8878
‘Platinum’ in the patent
full-text
44,541
‘Platinum’ in the patent
full-text but not title,
abstract or claims
35,663
Table II shows the top fifteen assignees for
each set of results in Table I. It shows that we
might expect to obtain quite different results for
the various searches, even though the keyword is
the same in each case. Apart from Micron
Technology Inc, which heads up each list, there are
some very significant differences. Engelhard (now
BASF Catalysts) comes in at number five in the
‘title or abstract’ search but does not appear in the
‘title, abstract or claims’ or full-text searches. On
the other hand, the Semiconductor Energy
Laboratory, while it does not appear in the ‘title or
abstract’ search, and only reaches number twelve
in the ‘title, abstract or claims’ search, comes in at
number two in the full-text search.
Pfizer is another good example. Like
Semiconductor Energy Laboratory, this company
232
Table II
Search Results by Top Fifteen Assignees for Patents in the U.S. Granted Patent Collection,
Published between 1st January 2001 and 31st December 2007
Rank
‘Platinum’ in patent title
or abstract (1611 patents)
‘Platinum’ in patent title, abstract
or claims (8878 patents)
‘Platinum’ in patent full-text
but not title, abstract or claims
(35,663 patents)
1
Micron Technology Inc
Micron Technology Inc
Micron Technology Inc
2
General Electric
General Electric
Semiconductor Energy Laboratory
3
Shin-Etsu Chemical Co
IBM
Fuji Photo Film Co Ltd
4
UOP LLC
Samsung Electronics Co Ltd
Eastman Kodak
Advanced Micro Devices Inc
Canon KK
1
5
Engelhard Corporation
6
Dow Corning
Matsushita Electric Industrial
Co Ltd
Matsushita Electric Industrial
Co Ltd
7
Matsushita Electric Industrial
Co Ltd
Shin-Etsu Chemical Co
General Electric
8
Texas Instruments Inc
Intel Corp
3M Innovative Properties Co
9
Dow Corning Toray Silicone
Infineon Technologies AG
IBM
10
IBM
Hitachi Ltd
NGK Insulators Ltd
11
Advanced Cardiovascular
Systems
Institut Francais du Petrole
Seiko Epson
12
Samsung Electronics Co Ltd
Semiconductor Energy Laboratory
Medtronic Inc
13
Honeywell International Inc
UOP LLC
Pfizer
14
Infineon Technologies AG
Texas Instruments Inc
Sony Corp
15
BASF
Hewlett-Packard Development Co
Hitachi Ltd
1
Now BASF Catalysts
only appears in the top assignees from the full-text
search. One would expect Pfizer’s main interest in
platinum to be as a user of catalysts in pharmaceutical manufacturing, rather than as a developer of
new pgm-based technologies. Manual inspection of
selected Pfizer patents confirms this to be the case.
The Results List and Initial
Analysis
For the remainder of this paper we will be considering the results of searches based on the names
of the pgms in the patent title or abstract. We have
undertaken the search in the U.S., European and
PCT patent collections, for patent applications or
granted patents published in the period from 1st
January 1983 to 31st December 2007. The search
results have then been ‘deduplicated’ to exclude
Platinum Metals Rev., 2008, 52, (4)
patent family members filed in different geographical regions, to leave one patent per invention. The
final document list contains just over 13,540
patents.
Figure 1 shows a basic breakdown of these
patents by metal and by five-year timeslices.
Overall growth in pgm patents in the period from
1983 to 2007 is about 6% per annum. In the last
seven years, this growth rate has been nearly 13%.
However, growth in the number of patents by
individual metal is not completely uniform. There
has been somewhat higher growth for platinum,
ruthenium and iridium patents, and slightly lower
growth for palladium and rhodium, as shown in
Table III.
A comparison between the pgm patent picture
and that for a number of other metals (gold, silver,
233
Number of patents published
7000
6000
Osmium
5000
Iridium
4000
Fig. 1 PGM
patents by
metal –
number
published in
five-year time
periods
Ruthenium
3000
Rhodium
2000
Palladium
1000
Platinum
0
20
7
00
–2
03
2
00
–2
7
2
99
–1
98
93
19
19
99
–1
7
98
–1
88
83
19
19
Time period
nickel and cobalt) is shown in Figure 2. The number of patents on all these metals has increased.
However the rate of increase for pgms and gold is
considerably higher than that for nickel, cobalt and
silver. This is illustrated in Table IV by looking at
the earliest (1983–1987) and latest (2003–2007)
time periods.
Figure 3 shows the importance of these metals
in selected technology areas. The analysis was
based on selected International Patent
Classification (IPC) codes (4).
Patent Mapping
The Aureka ThemeScapeTM tool (3) was used to
create a visualisation of the pgm document list
described above. The results are shown in Figure 4.
The resulting map looks like a mountainous island
surrounded by sea. The visualisation is helpful
because ThemeScape groups together similar documents and labels these groups according to
frequently used key terms found within those
groups. The more documents contained within
each group, the higher the ‘mountain’ appears. The
automatic labelling sometimes produces meaningful headings (e.g. silicone, rubber, polysiloxane),
but sometimes these are less obviously meaningful
(compounds, preparation, reaction). Where necessary these can be edited following an inspection of
documents contained within the groups.
The grey dots represent sample documents – in
this set of 13,540 documents only a small proportion are shown in this view, but more (or all)
documents will be shown when specific areas are
magnified. Clicking on specific dots will display the
Table III
PGM Patents by Metal: Number and Proportion of Patents Containing Specific PGMs
Published in Early (1983–1987) and Recent (2003–2007) Time Periods
Metal
Patents containing specific pgms
vs. total pgm patents, 1983–1987
Patents containing specific pgms
vs. total pgm patents, 2003–2007
Number
Number
Proportion, %
Proportion, %
Platinum
Palladium
Rhodium
Ruthenium
Iridium
Osmium
840
659
408
349
184
56
46
36
22
19
10
3
2265
1452
689
1024
613
189
52
33
16
23
14
4
1
18331
–
43921
–
Total
1
This is not the arithmetic sum as more than one pgm can appear in any given document
Platinum Metals Rev., 2008, 52, (4)
234
Number of patents published
20000
18000
16000
14000
12000
10000
8000
6000
4000
2000
0
Cobalt
Nickel
Silver
Gold
Fig. 2
Comparison of
pgms with
selected other
metals –
number of
patents
published in
five-year time
periods
PGM
20
00
7
2
7
00
–2
03
–2
99
2
7
99
–1
98
93
19
19
–1
98
–1
88
83
19
19
Time period
Heterogeneous catalysts
Technology area
Semiconductors or Electronics
PGM
Homogeneous catalysts
Gold
Fuel cells and batteries
Silver
Nickel
Coated products
Cobalt
Alloys
Medical
0
500
1000
1500
Number of patents
2000
Fig. 3 Relative importance of various metals in selected technology areas, by IPC code, for the time period
between 1st January 2003 and 31st December 2007
Table IV
PGM Patents vs. Other Metals: Number and Proportion of Patents Containing Specific
Metals Published in Early (1983–1987) and Recent (2003–2007) Time Periods
Metal
PGMs
Gold
Silver
Nickel
Cobalt
1
Total
Patents containing specific metals
vs. total metal patents, 1983–1987
Patents containing specific metals
vs. total metal patents, 2003–2007
Number
Number
Proportion, %
Proportion, %
1833
646
2009
2200
1279
28
10
31
34
20
4392
2152
4062
4626
2441
31
15
28
32
17
65361
–
14,2931
–
1
This is not the arithmetic sum as more than one pgm can appear in any given document
Platinum Metals Rev., 2008, 52, (4)
235
Fig. 4 PGM patent map covering granted patents or patent applications published between 1st January 1983 and 31st
December 2007
original document. The contour lines enclosing
particular areas can be used to select groups of
documents for inspection or further analysis.
In Figure 5, we have further processed the basic
map shown in Figure 4 in two ways. Firstly, to create a timeslice covering documents published only
in the period January 2003 to December 2007; secondly, to show patents on platinum as red dots and
patents on palladium as green dots. Where specific documents cover both platinum and palladium,
these are shown as white dots.
The reason for this exercise is to show the relative importance of particular metals in specific
technology areas. For example, the ‘silicone, rubber, organopolysiloxane’ and ‘fuel cell, fuel,
electrode’ areas are dominated by red dots, indicating that platinum is the preferred metal in these
applications. The ‘plating, deposited, substrate’
region is dominated by green dots, confirming the
importance of palladium in electronic applications.
Platinum Metals Rev., 2008, 52, (4)
The ‘exhaust, engine, oxide’ area contains many
red, green and white dots, indicating that both metals may be used in emission control applications.
Figure 6 is a similar image showing the minor
metals rhodium, ruthenium, iridium and osmium.
Of particular interest here are the two boxed
areas, the first just left of centre, the second centre right. These contain a cluster of mainly light
blue dots (ruthenium) and dark blue dots (iridium), respectively. Comparison of the number of
dots with the same areas in Figure 7, covering the
1993 to 1997 timeslice, shows a marked increase
in the numbers of iridium and ruthenium patents
published in 2003–2007. These are examples of
emerging technologies. Magnification of one of
these areas (see Figure 8) shows that this area
includes many patents on organic light emitting
diodes (OLEDs), which is an important potential
new application for iridium-based fluorescent or
phosphorescent dopants. OLEDs (see also
236
Fig. 5 PGM patent map timeslice 2003–2007, showing occurrences of platinum patents (red dots), palladium patents
(green dots), and patents covering both platinum and palladium (white dots)
References (5, 6)) are solid-state devices composed of thin films of organic molecules that
create light with the application of an electric current. Compared with conventional light-emitting
diodes (LEDs) or liquid crystal displays (LCDs),
OLEDs provide brighter, crisper displays which
require less power. It has been discovered that in
some iridium complexes, strong spin-orbit coupling leads to singlet-triplet mixing, ideal for
highly efficient electrophosphorescence required
for future OLEDs. Companies with pgm patents
in the OLED area currently include DuPont
(U.S.A.), Samsung (Korea), LG Electronics
(Korea), Idemitsu Kosan (Japan) and Konica
Minolta (Japan).
Further analysis of the map shows that ruthenium-based interconnects and electrodes,
iridium-based capacitor materials, new magnetic
materials containing iridium or ruthenium, ruthenium-based metathesis catalysts (for example
Platinum Metals Rev., 2008, 52, (4)
Grubbs’ catalyst) and the application of ruthenium in silane production are other emerging
technology areas.
The Non-Patent Literature
While patents are an extremely important
source of technical and commercial intelligence,
there is also a huge amount of non-patent literature covering the pgms. This is illustrated in Figure
9, which compares the size of the patent literature
on ruthenium with that of the non-patent scientific literature on the uses of this metal in
chemistry-related areas. The top ten uses for
ruthenium in the non-patent literature, based on
controlled index terms used in the Chemical
Abstracts database, are shown in Table V.
Specialised software tools such as STN®
AnaVistTM (7) are now available to assist with the
analysis of non-patent (as well as patent) literature,
similar to that described above for the patent data.
237
Fig. 6 PGM patent map timeslice 2003–2007, showing occurrences of rhodium patents (yellow dots), iridium patents
(dark blue dots), ruthenium patents (light blue dots), osmium patents (purple dots), and patents covering two or more
minor metals (white dots)
Table V
Top Ten Uses for Ruthenium from the Non-Patent
Chemical Literature, 2003–2007
Publication index term
Fuel cells
Oxidation catalysts
Hydrogenation catalysts
Nanoparticles
Oxidation, electrochemical
Carbon black, uses
Fluoropolymers, uses
Magnetisation
Spin valves
Vapour deposition process
Proportion of total,
2003–2007, %
11.2
10.7
9.4
5.2
4.4
4.1
3.7
3.7
3.7
3.4
Conclusions
The patent literature is an extensive and
detailed source of information on existing and
potential new applications for the pgms. At the
Platinum Metals Rev., 2008, 52, (4)
time of writing, there are in the region of 13,540
inventions, covering the period from January
1983, in which the use of one or more pgms is a
key part of the inventive step. There are many others in which pgms may be used, for example as
part of a complex organic synthesis route. Growth
of this literature is expected to continue to
increase at a rate slightly higher than that of certain base metals.
Patent mapping tools can be used to identify
key areas of development and ‘hot spots’ of
activity which may lead to future volume applications. ‘Hot spot’ areas for the minor metals
ruthenium and iridium currently include iridium
in organic light emitting diodes (OLEDs), ruthenium-based interconnects and electrodes,
iridium-based capacitor materials, new magnetic
materials containing iridium and/or ruthenium,
and the application of ruthenium in silane
production.
238
Fig. 7 PGM patent map timeslice 1993–1997, showing occurrences of rhodium patents (yellow dots), iridium patents
(dark blue dots), ruthenium patents (light blue dots), osmium patents (purple dots), and patents covering two or more
minor metals (white dots)
Fig. 8 Magnified view of
centre-right box shown in
Figure 6 for timeslice
2003–2007, showing
occurrences of iridium
patents (dark blue dots),
ruthenium patents (light
blue dots), and patents
covering two or more
minor metals (white dots)
Iridium
OLED
Electroluminescent
Platinum Metals Rev., 2008, 52, (4)
239
Number of publications
3500
3000
2500
Patents
2000
1500
Fig. 9 Trends in the
non-patent literature –
number of publications
in patent and non-patent
literature for ruthenium
Non-patents
(uses)
1000
500
0
20
03
–2
7
2
00
00
7
2
99
–2
–1
98
93
19
19
7
99
98
–1
–1
88
83
19
19
Time period
References
1
2
3
4
I. Wishart, Platinum Metals Rev., 2005, 49, (2), 98
R. Seymour, Platinum Metals Rev., 2006, 50, (1), 27
®
Thomson Reuters, Scientific: Products: Aureka :
http://scientific.thomsonreuters.com/products/aureka/
World Intellectual Property Organization, IP
Services, WIPO International Classifications:
5
6
7
http://www.wipo.int/classifications/
J. A. G. Williams, Platinum Metals Rev., 2007, 51, (2),
85
R. J. Potter, Platinum Metals Rev., 2008, 52, (3), 155
®
CAS, STN AnaVistTM:
http://www.cas.org/products/anavist/
The Author
Richard Seymour is the Head of Technology
Forecasting and Information at the Johnson
Matthey Technology Centre, U.K. He is
interested in the use of information in the
areas of competitive intelligence and
commercial development.
Platinum Metals Rev., 2008, 52, (4)
240
DOI: 10.1595/147106708X363888
Creep 2008: 11th International Conference
on Creep and Fracture of Engineering
Materials and Structures
HIGH-TEMPERATURE BEHAVIOUR OF PLATINUM GROUP METALS
Reviewed by J. Preußner, R. Völkl and U. Glatzel*
Metals and Alloys, University Bayreuth, Ludwig-Thoma-Straße 36b, D-95447 Bayreuth, Germany;
*E-mail: [email protected]
From 4th to 9th May 2008, 149 participants met
in Bad Berneck, a small village close to Bayreuth,
Germany, for the 11th International Conference
on Creep and Fracture of Engineering Materials
and Structures, in short, Creep 2008 (1, 2). The
attendees came from twenty-two different nations
all over the world to participate in Creep 2008,
organised by Uwe Glatzel (Metals and Alloys,
University Bayreuth, Germany) and by Gunther
Eggeler (Research Group for Materials Science
and Engineering, Ruhr-University Bochum,
Germany). During five days 111 oral presentations
were given. The programme was divided into
twenty sessions: General I–III, Steel I–VI, Nickel
I–III, Refractory I–II, Ti & TiAl, Magnesium, Cu
& MMC (Metal Matrix Composites), Steel
Welding, Light Metals and Testing Techniques.
Creep deformation is a time-dependent deformation of materials at high temperatures. Hence,
the topics of the conference included modelling
and simulation of creep deformation, high resolution microanalysis and the development of new
high-temperature materials. During the meeting
engineers and scientists shared their experience
and knowledge in order to explore new materials
and applications. A short overview of the talks
related to platinum group metals (pgms) is given
here.
L. A. Cornish (University of the Witwatersrand,
Johannesburg, South Africa) gave an overview of
the ‘Derivation of the Creep Properties of Twophase Pt-Al-Cr-Ru Alloys by Modelling’. She
presented the development of two-phase Pt-based
alloys, which have a similar structure to the wellknown and very successful nickel-based
Platinum Metals Rev., 2008, 52, (4), 241–242
superalloys. Progress in developing a thermodynamic database for phase diagram predictions was
also presented (see also References (3–5)). The aim
of this work is to use these predictions to calculate
the volume fraction of the Pt3Al precipitates, then
combine microstructural data derived from a series
of different alloy compositions to develop a
relationship for the stability of the precipitates. As
she pointed out, this allows the size and precipitate
distribution against temperature to be modelled for
a given alloy composition in the (Pt) and (Pt3Al)
phase field in the Pt-Al-Cr-Ru quaternary system.
K. Maruyama (Tanaka Kikinzoku Kogyo K.K.,
Japan) reviewed ‘High Temperature Creep of
GTH (Gottsu-Tsuyoi Hakkin)’. In his talk, hightemperature creep properties of GTH and GTHR,
which are trade names of oxide dispersion
strengthened platinum alloys developed by the
Tanaka Kikinzoku Group, are explained and compared with commercial platinum and
platinum-rhodium alloys. It was presented that,
comparing the same rupture time; GTHR is several times stronger than the normal Pt-10% Rh alloy,
which may be of interest for the glass melting
industry for the production of liquid crystal displays and optical glass and the spinning of glass
fibres.
The presentation of J. Preußner (Metals and
Alloys, University Bayreuth, Germany) addressed
the ‘Determination of Phases in the System Pt-AlCr-Ni and Thermodynamic Calculations’. Pt base
alloys have been developed at the Metals and
Alloys group to receive creep, oxidation and corrosion resistant alloys for high-temperature
applications with room temperature ductility.
241
Thermodynamic modelling has been used to support the alloy development. The Cr-Pt system has
been reassessed with the CALPHAD method
based on experimental data and first-principles
calculations. He presented a calculated Cr-Ni-Pt
ternary phase diagram and an outlook on the calculation of the quaternary Pt-Al-Cr-Ni system.
R. Völkl (Metals and Alloys, University
Bayreuth,
Germany)
summarised
the
‘Development of a Precipitation Strengthened Pt
Base Superalloy’. He reviewed the process of
designing an alloy with good mechanical properties and excellent oxidation resistance up to very
high temperatures. Similarly to the approach of
Cornish (described above), Pt-Al-Cr has been used
as a starting point for alloy development. A variety
of ternary additions to the Pt-Al base have been
investigated to secure the L12 structure of the
hardening Pt3Al phase. He explained that Ni has
been added for solid solution strengthening. A
comparison to the common alloy development
route in the industry has been shown.
P. Panfilov (Urals State University,
Ekaterinburg, Russia) gave a presentation ‘On
Specific Feature of Plastic Deformation in
Iridium’. He stated that the refractory f.c.c.-metal
Ir, with a melting point of 2443ºC, exhibits excellent mechanical properties at high temperatures.
According to experiments he presented, the deformation behaviour of Ir is well in accordance with
empirical knowledge on f.c.c.-metals, while some
features of Ir seem to be puzzling. He compared
the deformation behaviour of single crystals to
polycrystalline material at different temperatures.
One feature of the deformation behaviour of Ir,
he pointed out, is that single crystals show a
remarkable total elongation, but no necking,
whereas polycrystals only reach a small deformation, but considerable necking. With the help of
transmission electron micrographs, Panfilov
explained the dislocation structures in deformed Ir
samples.
A collection of the conference contributions
will be published in a special issue of the journal
Materials Science and Engineering A (6). The 12th
International Conference on Creep and Fracture
of Engineering Materials and Structures, Creep
2011, will be held in Japan, and will be chaired by
Kouichi Maruyama (Tohoku University) and
Hideharu Nakashima (Kyushu University).
References
1
2
3
4
5
6
Creep 2008: 11th International Conference on
Creep and Fracture of Engineering Materials and
Structures:
http://www.metalle.uni-bayreuth.de/creep2008
Abstract Book for Creep 2008:
http://www.metalle.uni-bayreuth.de/creep2008/
abstractbook_Creep2008.pdf
L. A. Cornish, R. Süss, A. Watson and S. N. Prins,
Platinum Metals Rev., 2007, 51, (3), 104
A. Watson, R. Süss and L. A. Cornish, Platinum
Metals Rev., 2007, 51, (4), 189
J. Preußner, S. N. Prins, M. Wenderoth, R. Völkl
and U. Glatzel, Platinum Metals Rev., 2008, 52, (1), 48
Mater. Sci. Eng. A, in press (publication date will be
early 2009)
The Reviewers
Johannes Preußner is a scientific researcher
and Ph.D. student at the Chair of Metals and
Alloys at the University Bayreuth, Germany.
His main interests include modelling and
simulation in materials science and new
high-temperature materials.
Dr.-Ing. Rainer Völkl is senior researcher at
the Chair of Metals and Alloys, University
Bayreuth, Germany. His main fields of
research include alloys of platinum group
metals as well as nickel base alloys, testing
of mechanical properties at high
temperatures and electron microscopy.
Professor Dr.-Ing. Uwe Glatzel is head of the
Chair of Metals and Alloys at the University
Bayreuth, Germany. His work has had a big
impact on the development of modern hightemperature alloys, mainly nickel base
superalloys. He advises several research
groups, including those working on
platinum-based superalloys and other alloys
for high-temperature applications, laser metallurgy, material
analysis and artificial knee joints.
Platinum Metals Rev., 2008, 52, (4)
242
DOI: 10.1595/147106708X366975
Global Release Liner Industry
Conference 2008
OPTIMISED TECHNOLOGIES ARE EMERGING WHICH REDUCE PLATINUM USAGE
IN SILICONE CURING
Reviewed by Andrew J. Holwell
Johnson Matthey, Precious Metals Marketing, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.;
E-mail: [email protected]
Global Release Liner Industry Conference 2008
was organised by AWA Alexander Watson
Associates BV and took place from 6th to 8th
February 2008, at the Hilton Amsterdam Hotel,
The Netherlands (1). It was attended by all the
major players in the silicones industry, major label
and paper manufacturers and representatives of
the precious metals industry. The conference
focused much attention on the development of
next-generation low platinum catalyst solutions
and the potential for complete removal of platinum from silicone curing systems. This review
describes the technical developments, their related
benefits and shortcomings, and summarises the
trends expected to prevail in the release liner
industry during the next few years. The release
liner industry is an important sector of the overall
market for silicones.
Background
Silicones, or polyorganosiloxanes, are used in a
variety of applications, particularly in pressure-sensitive adhesives and release coatings. A key market
in this sector is that of release liner coatings for
labels and tapes, where the good adhesion and
clean release properties of silicone release coatings
are highly desirable.
(a)
Pt
catalyst
R3SiH + H2C=CHR'
R3SiCH2CH2R' (i)
Karstedt’s catalyst (chloroplatinic acid-symdivinyltetramethyldisiloxane complex) is a Pt(0)
complex containing vinyl-siloxane ligands, and it
initiates the addition of a silicon–hydrogen bond
across a carbon–carbon double bond, known as
curing, which hardens the silicone by crosslinking siloxane chains, Figure 1. The reaction, at
temperatures in the region of 80 to 120ºC, is carried out in a platinum-containing Karstedt’s
catalyst bath in which the silicone is cured rapidly as the paper label, or ‘labelstock’, is applied to
its backing, forming a release coating between
the two layers on a sub-second timescale. Free
radical-based alternatives to platinum catalysis,
initiated either by ultraviolet (UV) light or an
electron beam, can be used to generate the radical initiator, but require labile groups such as
epoxides or acrylates and thus the properties of
the cured silicone vary from conventional
silicones.
(b)
CH3
(CH3)3Si
Platinum is widely used as a catalyst for the curing of these silicones by promoting a
hydrosilylation reaction, Reaction (i), (2):
O
Si
CH3
O
Si
x
H
CH3
CH3
CH3
O
Si(CH3)3
y
Si
CH3
O
Si
CH3
CH3
O
Si
CH3
O
x
Si
y
CH3
Fig. 1 (a) Silicone monomer typically used in solventless platinum-catalysed hydrosilylation reactions;
(b) Conventional crosslinker for platinum-catalysed hydrosilylation reactions
Platinum Metals Rev., 2008, 52, (4), 243–246
243
Platinum in the Release Liner
Industry
Presentations were given by silicones suppliers Dow Corning, Bluestar Silicones and Wacker
Silicones, and perhaps the hottest topic of the
conference was that of platinum, its price and
ways to reduce its usage. Platinum-catalysed
thermal curing remains the industry standard
approach and because the catalyst is irretrievably
lost in the product, the cost of platinum is one
of the biggest challenges facing the industry
today.
Highlights related to platinum included a joint
presentation by Norm Kanar (Dow Corning,
U.S.A.) and Wolfgang Wrzesniok-Rossbach (W. C.
Heraeus, Germany) entitled ‘Platinum Challenges:
Trends and Developments’, showcasing the cost
benefits of Dow Corning’s low platinum product
series. There was also a paper by Karsten
Schlichter (Bluestar Silicones, France), entitled
‘Radiation Curing Silicone Release Systems, the Pt
Alternative?’, appraising a range of curing
chemistries. According to this presentation, the
market split between platinum and radiation cured
systems is expected to stand at around 80:20 by
2015 compared to 85:15 at present. A small and
diminishing share of the market uses solvent-based
tin-catalysed emulsions, but this is expected to fall
to zero within the next few years, according to
these projections. Taking a slightly different angle,
Hans Lautenschlager (Wacker Silicones, Germany)
described smarter ways of monitoring and using
silicone in his presentation ‘More or Less
Silicone?’.
Growth in the silicones industry is strongly
linked to growth in consumer spending, as
labelstock is primarily a consumer-driven industry. Annual global growth of around 5 per cent
is expected for the next few years. In terms of
platinum uptake, industry growth will be at least
offset by the increased use of low platinum
solutions, particularly when platinum prices are
high. During this conference, platinum successively set then-record high prices, fixing in
London at U.S.$1852 per troy ounce on 7th
February and U.S.$1860 per troy ounce on 8th
February (3).
Platinum Metals Rev., 2008, 52, (4)
Low Platinum Technologies
Johnson Matthey estimates that the silicones
industry worldwide used around 180,000 troy
ounces (5.6 tonnes) of platinum in 2007 (4), which
at average Johnson Matthey base prices for the
year of U.S.$1307 per troy ounce, is worth around
U.S.$235 million; in the eighteen months from the
start of 2007 to July 2008, the price of platinum
almost doubled (3). This accelerated the development of low platinum technologies, which have the
advantage of being largely drop-in replacement
systems for existing coating units, unlike free radical initiated systems. Through advanced
engineering of the silicone polymers and crosslinkers, Dow Corning has developed a system which
allows the use of a catalyst bath containing only
25–35 ppm platinum, compared to the standard
100 ppm typically in use around the industry. Dow
Corning claims that its “branched polymers [and] a
new crosslinker structure… [which] enables cure
of the release coating at platinum catalyst levels as
low as 25 ppm” (5) can overcome operational and
performance issues typically seen with the modified components in the radiation-cured field.
Bluestar Silicones and other companies market
similar solutions, which are commercially available.
The feeling in the industry is that platinum reduction, rather than widespread uptake of UV
solutions, is likely to be the key trend in the next
decade. The technical barriers to reduced platinum
usage are less significant, less costly and appear
closer to being resolved.
The market share of platinum-based solventless
emulsions remains at around 85% according to
Bluestar Silicones, who themselves offer a platinum-free option to paper manufacturers. This
level of market share is unlikely to decline significantly in the near future, although as explained
below, platinum-free UV cured systems will continue to take some market share, most likely in
lower performance applications.
Non-Platinum Technologies
Free radical-initiated curing was pioneered by
Goldschmidt GmbH, latterly Degussa and now
Evonik, in the early 1980s and has gradually taken
limited market share since that time. The technol-
244
ogy uses unconventional side chains such as
epoxy and acrylate groups to generate free radicals
at ambient temperature, usually by UV activation,
as shown in Figure 2, (6). Occasionally cationic
curing can be used, although only under certain
process and substrate conditions. Evonik state
that ‘post-curing’ in both UV-initiated and in particular cationic systems can be a problem (7), in
other words the rate of curing is not comparable
to the platinum-catalysed reaction. The UV
process itself displays operational and product
performance limitations, in terms of clean release
and rate of curing, which has a direct impact on
the throughput of the coating equipment. It is
generally thought that both coat weights and curing times are higher for radiation-cured silicones,
although a number of companies claim to have
achieved similar curing times and therefore
throughput to the conventional process. This
would represent a significant technical advance,
and may promote the transition to non-platinum
technologies in the future.
In a paper entitled ‘The Influence of the
Release Liner on Label Properties’, Hervé Vigny
(Label Experts, France) described a phenomenon
known as the ‘zippy effect’, observed in UV-initiated systems. After curing, the adhesion of the
label to the release liner takes some time to stabilise, compromising the clean release
performance of the product. Although the effect is
not fully understood at this time, the cause is widely thought to be the modified side chains which
are essential for UV-initiated processes.
Perhaps the greatest barrier to a move to UV
(a)
Conclusions
Global Release Liner Industry Conference
2008 focused on the key topic of platinum usage
in silicone curing applications and potential opportunities for reducing the amount of platinum used.
These include the use of advanced silicone
monomers and crosslinkers to reduce the amount
of platinum catalyst required, or the use of alternative curing technologies, specifically UV-initiated
free radical curing. Low platinum solutions are
becoming available to the release liner industry
from silicones manufacturers and are expected to
achieve significant market share within a few years,
as high platinum prices (at the time of this conference) stimulate efforts to use less of the precious
metal. Doubts over the financial viability of
installing and using radiation curing technology
remain, as do technical limitations of the product
and process, meaning that this production method
will only be used for around twenty per cent of
release liner curing applications in the next decade,
with the balance still to use platinum catalysts.
(b)
CH3
(CH3)3Si
technologies is the significant capital and operational expenditure needed to install the UV light
source and its related equipment. There are also
process control issues associated with the requirement to carry out the reaction in an inert
atmosphere of nitrogen. Opinion varies on
whether the transition is financially viable at all,
even at the platinum prices that were current at the
time of the conference. In an industry relatively
averse to change, conventional methodology is not
expected to be displaced quickly.
O
Si
CH3
CH3
O
Si
CH3
O
Si(CH3)3
R
x
O
Si
CH3
O
O
(CH3)3Si
y
CH3
O
Si
x
O
Si(CH3)3
R
O
y
R = (CH2)n
Fig. 2 (a) Acrylate-based crosslinked silicone, as produced by UV-cured process; (b) Epoxy-based crosslinked silicone,
as produced by UV-cured process (6)
Platinum Metals Rev., 2008, 52, (4)
245
Acknowledgements
®
Publically available literature from Dow
Corning (8), Bluestar Silicones (9), Wacker
Silicones (10) and Evonik (11) was used as background information for this review. Global Release
Liner Industry Conference 2008 was organised by
AWA Alexander Watson Associates BV.
References
1 Global Release Liner Industry Conference 2008:
http://www.awa-bv.com/?c=event&t=brochure&id=35
2 L. N. Lewis, J. Stein, Y. Gao, R. E. Colborn and G.
Hutchins, Platinum Metals Rev., 1997, 41, (2), 66
3 Johnson Matthey, Platinum Today, Price Charts:
http://www.platinum.matthey.com/prices/price_
charts.html
4 Johnson Matthey Precious Metals Marketing, U.K.
5 ‘Release System Information Guide, Syl-Off
Advantage Series Solventless Release Coatings from
Dow Corning’, Dow Corning Corporation, U.S.A.,
2006
®
6 ‘Free Radical Curing TEGO RC Silicones, A
Practical Guide’, Goldschmidt GmbH, Essen,
Germany, 06/2007
7 ‘Goldschmidt Radiation Curable Silicones, An
Overview’, Goldschmidt GmbH, Essen, Germany,
08/2007
8 Dow Corning Silicones:
http://www.dowcorning.com/
9 Bluestar Silicones:
http://www.bluestarsilicones.com/
10 Wacker Silicones:
http://www.wacker.com/cms/en/wacker_group/
divisions/silicones/silicones.jsp
11 Evonik Industries: http://corporate.evonik.com/
The Reviewer
Andy Holwell is a Market Analyst for
Johnson Matthey PLC. He received an
MChem in Chemistry from the University of
York, U.K., in 2004. He joined Johnson
Matthey in September 2005, initially as a
Process Development Chemist specialising
in autocatalyst development, and has held
his current position since January 2007.
Mr Holwell specialises in pgm market research in the chemical,
petroleum and energy sectors and is a member of the Royal
Society of Chemistry.
Platinum Metals Rev., 2008, 52, (4)
246
DOI: 10.1595/147106708X364481
“The Periodic Table: Its Story and
Its Significance”
BY ERIC R. SCERRI (University of California, Los Angeles, U.S.A.), Oxford University Press, Inc, New York, U.S.A., 2007,
368 pages, ISBN 978-0-19-530573-9, £19.99, U.S.$35.00
Reviewed by Michael Laing
Professor Emeritus, University of KwaZulu-Natal;
61 Baines Road, Durban 4001, South Africa; E-mail: [email protected]
The author, Eric Scerri, teaches chemistry and
the history and philosophy of science at the
University of California, Los Angeles, U.S.A. He
has published widely about the development and
structure of the Periodic Table, and is the Editorin-Chief of the journal Foundations of Chemistry (1).
He was an invited speaker at the 2003 conference, “The Periodic Table: Into the 21st
Century” (see also (2)). This book is timely – it is
over thirty years since books about the periodic
system by Mazurs (3) and van Spronsen (4) were
published.
It is not simply a plodding, step by step
history nor a collection of all known tabular
arrangements of the elements. The author
describes developments, explains what led to
them, comments on them and discusses their
implications. He carefully describes the philosophical thinking of Dimitri Mendeleev and how
he differentiated between “the element” and
“simple substance”, a difference that was critical
in helping Mendeleev deduce the periodic law
and system.
One must ask: for whom is this book written?
It is for all chemists. What is there for the
chemist involved with the platinum group metals
(pgms)? Mendeleev in 1869 (5, 6) specifically
quotes the similar atomic weights of platinum,
iridium and osmium as being an important foundation of his periodic system. Now jump forward
fifty years to quantum mechanics and the deduction of electron configurations of the elements.
The commonly held doctrine says that the chemical properties of an element are determined by
the configuration of the valence electrons. This
implies that elements in the same group, having
Platinum Metals Rev., 2008, 52, (4), 247–248
similar chemical properties, will have the same
electron configurations. Unfortunately, this is
not true. An example is the group: nickel,
palladium, platinum: Ni 4s 2 3d 8 ; Pd 5s 0 4d 10;
Pt 6s1 4f 14 5d 9 . It is evident to any pgm chemist
that these electron configurations do not fit the
chemistry of refining. Conversely, we have the
group copper, silver, gold: Cu 4s1 3d 10; Ag 5s1 4d 10;
Au 6s1 4f 14 5d 10, whose common oxidation states
are Cu2+, Ag1+, Au3+. The author discusses these
problems.
The brightly coloured cover is attractive and
calls out: “Read me”. There are many black-andwhite portraits of chemists. Unfortunately, those
of de Chancourtois, Newlands and Odling are
missing although their contributions are discussed at length. There is one surprising
omission. There is no current form Periodic
Table. Similarly it would have been valuable to
have had the 1950 short form “W. M. Welch
Scientific Company” table for comparison,
known as the Periodic Chart of the Atoms.
There is a very complete set of references and
notes at the back of the book which are keyed to
the relevant pages in the text. These are a mine of
information for those who want to further pursue this interesting subject.
There is one surprising and disappointing
shortcoming. There seem to be a larger-thannormal number of printing errors. Some examples are: p. 129, it is stated that “Based on its
formation of tetravalent compounds, Mendeleev
realized that uranium had a predominant valence
of 4, as do such elements as chromium.” (sic);
p. 217, iutetium (for lutetium); p. 239, 4s 2 3d
should be 4s 2 3d 9 for copper. There are others,
247
which will (I hope) be corrected in the next
printing. This book deserves better editing and
proofreading.
This is a book for the thinking chemist. It
reflects the personal interests of the author.
Scerri advocates a different layout: the left-step
table of Janet, in which the long periods follow
the Madelung rule and begin with Group 3 elements: boron, aluminium; scandium, yttrium;
lanthanum, actinium; and helium is above beryllium. His discussion of this topic is valuable. There
is no requirement that we agree with all of his
conclusions, but Eric Scerri makes us think, and
that, after all, is what good science is all about.
This is a book that is well worth reading.
References
1
2
3
4
5
6
Foundations of Chemistry, Philosophical, Historical,
Educational and Interdisciplinary Studies of
Chemistry, Editor-in-Chief Eric R. Scerri, Springer,
The Netherlands:
http://www.springer.com/philosophy/philosophy+
of+sciences/journal/10698
“The Periodic Table: Into the 21st Century”, eds. D.
H. Rouvray and R. B. King, Research Studies Press,
Baldock, Hertfordshire, U.K., 2004
E. G. Mazurs, “Graphic Representations of the
Periodic System During One Hundred Years”, 2nd
Edn., University of Alabama Press, Alabama, U.S.A.,
1974
J. W. van Spronsen, “The Periodic System of
Chemical Elements: A History of the First Hundred
Years”, Elsevier, Amsterdam, The Netherlands,
1969
D. Mendeleev, Zhur. Russ. Khim. Obshch., 1869, 1, 60
D. Mendelejeff, Z. Chem., 1869, 12, 405
The Reviewer
Michael Laing was born in Durban, South Africa, and obtained his B.Sc.
(Hons) and M.Sc. degrees from the University of Natal in 1960. He earned
his doctorate from the University of California, Los Angeles, U.S.A., in
1964, and taught Inorganic Chemistry at the University of Natal, Durban,
from 1965 until he retired in 1997. He was twice Visiting Professor at
California State University, Northridge. His main field of interest was the
determination of molecular structure and bonding by single crystal X-ray
diffraction. He has also applied the X-ray powder diffraction method to the
analysis of materials such as urinary calculi, fossil-bearing breccia, failed
construction materials and intractables from a pgm refinery. He also
generated specialist academic courses, including metal extraction for chemical engineers, material
failures for architects and explosives for graduate chemists. He has over 200 publications in such
diverse fields as crystallography, bonding, coordination compounds, the Periodic Table, chemical
education and military history.
Platinum Metals Rev., 2008, 52, (4)
248
DOI: 10.1595/147106708X366704
John Ward Jenkins
A TRIBUTE
John Ward Jenkins
“The most exciting expression uttered by a
scientist, the one that heralds new discoveries and
inventions, is not ‘Eureka!’ …… but ‘That’s
funny’.” Isaac Asimov could have been thinking of
John Jenkins when he made this comment. John
was an instinctive lateral thinker, who could take a
simple laboratory test and turn it into one of the
most widely used techniques for characterising
complex solid materials, or could see the potential
for a new hydrogen-generating technology in a
spontaneous catalytic reaction that was taking
place in a small glass tube in a fume cupboard.
John was born on 23rd March 1932 in the
U.S.A., but grew up in England’s Lake District,
which instilled in him his love of nature and the
countryside. After studying Natural Sciences at
Cambridge University, U.K., he returned to the
U.S.A. to complete his education, with a Master’s
in Chemical Engineering at Princeton University.
His scientific career fell into two almost equal
halves. He worked for Shell in their Hydrocarbon
Cracking group at their MTM Process R & D
Platinum Metals Rev., 2008, 52, (4), 249–250
Laboratory in Texas for twenty years, before he
and his family finally settled in the U.K. when he
accepted a research post at the Johnson Matthey
Technology Centre in 1976. After a similar length
of time at the Technology Centre, he retired from
science in 1995, and he and his wife moved to a
farm in West Sussex.
While at Shell, John perfected the technique of
monitoring the controlled reduction of catalytic
materials (1), which many of us now recognise as
temperature-programmed reduction (TPR). His
role is often overlooked because TPR is one of
those inventions that was never patented.
However, as a non-proprietary technique, it could
be quickly adopted in laboratories around the
world, as news of it spread through the scientific
literature (see, for example, Reference (2)). John
was also particularly proud of the fact that its usefulness relies on the skill with which the results
are interpreted and not on the cost of the equipment! John’s personal TPR rig, which
hardly even registered as a capital asset, followed
249
alternatives, but also included fundamental
studies of platinum group metal (pgm) catalyst
behaviour (3). Latterly, though, his name was
invariably associated with the HotSpotTM reactor
(Figure 1), which he had invented in the late
1980s (4–6). The reformer can be used to generate H2 from hydrocarbon fuels and
oxygenates in the presence of a pgm-containing
catalyst, and may yet prove to be a key technology in a future hydrogen economy.
John Jenkins died on the 28th May 2008. He is
fondly remembered as a caring and influential
colleague and as an impressive scientist. Quite a
few of us working in catalysis have benefited
from his encouragement and wisdom, and many
more of us have benefited – perhaps unknowingly
– from the products of his inventive mind.
S. E. GOLUNSKI
From John’s former colleagues at the Johnson Matthey
Technology Centre, Blount’s Court, Sonning Common,
Reading RG4 9NH, U.K.
References
1
Fig. 1 A prototype of the HotSpotTM reactor for
hydrogen generation (4)
him from lab to lab throughout his career, and
could be stripped down and reassembled in the
space of a couple of hours.
At Johnson Matthey, John worked on a series
of innovative projects. These mostly addressed
environmental challenges, such as the replacement of base metal paint pigments by non-toxic
Platinum Metals Rev., 2008, 52, (4)
2
3
4
5
6
S. D. Robertson, B. D. McNicol, J. H. de Baas, S.
C. Kloet and J. W. Jenkins, J. Catal., 1975, 37, (3),
424
A. Jones and B. D. McNicol, “TemperatureProgrammed Reduction for Solid Materials
Characterization”, CRC Press, Boca Raton,
Florida, 1986
J. W. Jenkins, Platinum Metals Rev., 1984, 28, (3), 98
J. W. Jenkins and E. Shutt, Platinum Metals Rev.,
1989, 33, (3), 118
J. W. Jenkins, Johnson Matthey PLC, European
Patent Appl. 0,217,532; 1987
J. W. Jenkins, Johnson Matthey PLC, European
Patent Appl. 0,262,947; 1988
250
DOI: 10.1595/147106708X366858
ABSTRACTS
CATALYSIS – APPLIED AND
PHYSICAL ASPECTS
Comparative Study of Aromatization Selectivity
During n-Heptane Reforming on Sintered Pt/Al2O3
and Pt-Re/Al2O3 Catalysts
A. A. SUSU, J. Chem. Technol. Biotechnol., 2008, 83, (6), 928–942
The main products of n-heptane reforming on fresh Pt
were CH4, toluene and benzene, while on fresh Pt-Re,
only CH4 was obtained. For Pt/Al2O3, the products
ranged from only toluene at a sintering temperature (ST)
of 500ºC to CH4 at a ST of 650ºC, with no reaction at
800ºC. On Pt-Re/Al2O3, CH4 was the sole product at a
ST of 500ºC while only toluene was produced at a ST of
800ºC. Pt-Re/Al2O3 exhibited superior selectivity.
Carbon-Carbon Cross-Coupling Reactions under
Continuous Flow Conditions Using
Poly(vinylpyridine) Doped with Palladium
K. MENNECKE, W. SOLODENKO and A. KIRSCHNING, Synthesis,
2008, (10), 1589–1599
The coordinative immobilisation of an oxime-based
palladacycle to PVP/glass composites shaped as
Raschig rings or placed within a PASSflowTM microreactor affords devices that can be used for Pd-catalysed
C–C cross-coupling in the flow-through mode.
Reusability of the immobilised precatalyst as well as
reactions in the microwave field were investigated.
CATALYSIS – INDUSTRIAL PROCESS
Development of a Mild and Robust Method for
Large-Scale Palladium-Catalysed Cyanation of
Aryl Bromides: Importance of the Order of Addition
P. RYBERG,
Org. Process Res. Dev., 2008, 12, (3), 540–543
The title reaction is sensitive to cyanide poisoning
of the catalyst. For Pd(dba)2 + P(tBu)3 the order of
adding the reagents affected the performance of the
reaction. Addition of the cyanide source (Zn(CN)2) to
a preheated mixture of the aryl bromide, catalyst and
Zn dust was found to be critical. This reaction could
be run to full conversion within 3 h at 50ºC on a 6.7
kg scale. New efficient catalysts were identified.
CATALYSIS – REACTIONS
Enhancing H2 and CO Production from Glycerol
Using Bimetallic Surfaces
O. SKOPLYAK, M. A. BARTEAU and J. G. CHEN,
ChemSusChem,
2008, 1, (6), 524–526
TPD experiments revealed an increased production
of H2 from glycerol on the Ni surface monolayer on
Pt(111) (designated Ni-Pt-Pt(111)) as compared to
that on Pt(111), Ni(111) and Pt-Ni-Pt(111). Glycerol
reforming activity trends were similar to previous
results for ethylene glycol and EtOH. Smaller oxygenates can therefore be used as good models for
reforming of larger, biomass-derived oxygenates.
Platinum Metals Rev., 2008, 52, (4), 251–253
Efficient and Recyclable Catalyst of Palladium
Nanoparticles Stabilized by Polymer Micelles
Soluble in Water for Suzuki-Miyaura Reaction,
Ostwald Ripening Process with Palladium
Nanoparticles
I. P. BELETSKAYA, A. N. KASHIN, I. A. KHOTINA
KHOKHLOV, Synlett, 2008, (10), 1547–1552
and
A. R.
The Suzuki-Miyaura cross-coupling of ArX (X = I,
Br) with Ar'B(OH)2, catalysed by a Pd-containing
H2O-soluble micelle formed by PS-PEO and Ncetylpyridinium chloride, was investigated in H2O and
MeOH. The reaction was performed at ≤ 50ºC. The
catalyst can be recycled (5 runs) by ultrafiltration.
Direct Coupling of Arenes and Iodoarenes
Catalyzed by a Rhodium Complex with a Strongly
π-Accepting Phosphite Ligand
S. YANAGISAWA, T. SUDO, R. NOYORI and K. ITAMI, Tetrahedron,
2008, 64, (26), 6073–6081
A solution of [RhCl(CO)2]2 and P[OCH(CF3)2]3 in
dry toluene was stirred at 50ºC for 2 h under Ar to
synthesise RhCl(CO){P[OCH(CF3)2]3}2 (1). Under
the catalytic influence of (1) and Ag2CO3, the direct
C–H arylation of heteroarenes and arenes with
iodoarenes was achieved. The product biaryls were
obtained in good to excellent yields with high regioselectivity. This method can be used for thiophenes,
furans, pyrroles, indoles and alkoxybenzenes.
Vinyl and Ring-Opening Metathesis
Polymerization of Norbornene with Novel HalfSandwich Iridium(III) Complexes Bearing
Hydroxyindanimine Ligands
X. MENG, G.-R. TANG and G.-X. JIN,
Chem. Commun., 2008,
(27), 3178–3180
Half-sandwich Ir(III) complexes bearing hydroxyindanimine ligands were synthesised. The complexes
were used as catalysts for the ROMP and vinyl-type
polymerisation of norbornene in the presence of
methylaluminoxane (MAO). Pure ROMP polymer
and vinyl-type polymer were obtained depending on
the amount of MAO employed (0–30 equiv. for
ROMP and > 30 equiv. for vinyl-type polymerisation).
EMISSIONS CONTROL
Impact of Redox Conditions on Thermal
Deactivation of NOx traps for Diesel
K. M. ADAMS and G. W. GRAHAM, Appl. Catal. B: Environ.,
2008, 80, (3–4), 343–352
Lean and rich agings were investigated for a model
NOx trap, Pt-Ba/Al2O3. These were carried out at 950ºC
for 3 h, in air and in 1% H2/N2, respectively.
Pretreatments were examined for a commercially feasible NOx trap and two model NOx traps, Pt-Ba/Al2O3
and Pt-Ba-Ce/Al2O3, at 600ºC for 10 min, using feed gas
that simulated diesel exhaust under various conditions.
251
Enhanced Degradation of Tetrachloroethylene by
Green Rusts with Platinum
Graphite Nanofibers as Catalyst Support for
Proton Exchange Membrane Fuel Cells
and W. LEE, Environ. Sci. Technol., 2008, 42, (9),
3356–3362
H. XU, L. LU and S. ZHU, Chin. J. Catal., 2008, 29, (6), 542–546
J. CHOI
The reductive dechlorination of tetrachloroethylene
(PCE) by green rusts (GRs) (layered Fe(II)–Fe(III)
hydroxide solids with anions such as Cl–, SO42–,
CO32–, F–) in the presence of Pt was carried out using
a batch reactor system. The rate of PCE reduction
was greatly enhanced with the addition of Pt(IV)
(95% of PCE was removed in 30 h). PCE was mostly
transformed to acetylene. The estimated kinetic rate
constants of GR-Cl(Pt) increased significantly with an
incremental addition of Pt from 0.5 to 2 mM.
FUEL CELLS
Application of Atomic Layer Deposition of
Platinum to Solid Oxide Fuel Cells
Graphite nanofibres (GNFs) were prepared from
used C paper by a ball-milling method. 20% Pt was
loaded on the GNFs and Vulcan XC-72 to fabricate
Pt/GNFs and Pt/XC-72, respectively. CV showed
that Pt/GNFs had the same electrochemical surface
area (ESA) as Pt/XC-72. The electrochemical stability was measured for XC-72, GNFs, Pt/XC-72 and
Pt/GNFs electrodes by the constant potential oxidation. The peak current increased by 2% for GNFs
and 60% for XC-72. The corrosion current for
Pt/XC-72 was 1.4 times of that for Pt/GNFs. 84.7%
ESA was lost for Pt/XC-72 after oxidation for 60 h,
while only 37.2% ESA was lost for Pt/GNFs.
METALLURGY AND MATERIALS
X. JIANG, H. HUANG, F. B. PRINZ and S. F. BENT, Chem. Mater.,
Purification of Iridium by Electron Beam Melting
2008, 20, (12), 3897–3905
E. K. OHRINER,
Atomic layer deposition (ALD) was used to deposit
Pt thin films as an electrode/catalyst layer for SOFCs.
The measured fuel cell performance showed that
comparable peak power densities were achieved for
ALD-deposited Pt anodes with only one-fifth of the
Pt loading relative to dc-sputtered Pt anodes. A
micropatterned Pt structure was fabricated via areaselective ALD and used as a current collector
grid/patterned catalyst for the fuel cells.
The purification of Ir metal by electron beam melting has been characterised for 48 impurity elements.
The average levels of individual elemental impurities
in the starting Ir powder varied from 37 μg g–1 to 0.02
μg g–1. Li, Na, Mg, P, S, Cl, K, Ca, Mn, Co, Ni, Cu,
Zn, As, Pd, Ag, Cd, Sn, Sb, Te, Ba, Ce, Tl, Pb and Bi
were not detectable following the purification. No
significant change in the concentration of Ti, V, Zr,
Nb, Mo and Re was found. B, C, Al, Si, Cr, Fe, Ru,
Rh and Pt were partially removed by vaporisation.
Platinum Black Polymer Electrolyte Membrane
Based Electrodes Revisited
L. KRISHNAN, S. E. MORRIS and G. A. EISMAN,
J. Electrochem.
J. Alloys Compd., 2008, 461, (1–2), 633–640
Effects of Alloying Elements on Dendritic
Segregation in Iridium Alloys
Soc., 2008, 155, (9), B869–B876
Y. LIU, C. T. LIU, L. HEATHERLY and E. P. GEORGE,
Pt black-coated diffusion media of varying anode
and cathode catalyst loadings with H2/air demonstrated successful performance and stability for anode
catalyst loadings down to 0.25 mg cm–2 while operating on pure H2 and with a cathode loading of 0.62 mg
cm–2, without significant voltage losses. The voltage
losses from reducing the Pt black cathode loadings
(from 2.6 to 0.62 mg cm–2) are consistent with kinetic losses associated with the O2 reduction reaction
and lower electrocatalyst utilisation. Optimisation of
the three-phase interface – electrode, electrolyte and
reactant gas – was shown to be dependent on the efficacy of the membrane–catalyst layer interface.
Compd., 2008, 459, (1–2), 130–134
The Improved Methanol Tolerance Using Pt/C in
Cathode of Direct Methanol Fuel Cell
J. Alloys
The effects of alloying elements on dendritic segregation in ‘Ir-Nb’ (Ir-10Nb-0.5Zr-0.3W-0.3C-0.006Th,
at.%) and ‘Ir-Zr’ (Ir-4.5Zr-0.3W-0.3C-0.006Th, at.%)
alloys were investigated by Auger electron spectroscopy. The Nb addition induces significant
segregation of C and Th to dendritic interfaces. The
Zr addition leads to the formation of an Ir3Zr intermetallic phase, which results in less dendritic
segregation of C and Th. This dendritic segregation
may cause the severe cracking observed in the ‘Ir-Nb’
alloy after casting and heat treatment.
Synthesis of Ruthenium Particles by
Photoreduction in Polymer Solutions
M. HARADA and S. TAKAHASHI,
J. Colloid Interface Sci., 2008,
Y.-H. CHO, H.-S. PARK, Y.-H. CHO, I.-S. PARK and Y.-E. SUNG,
325, (1), 1–6
Electrochim. Acta, 2008, 53, (20), 5909–5912
Colloidal dispersions of poly(N-vinyl-2-pyrrolidone)-protected Ru particles were conveniently and
efficiently synthesised by the photoreduction of
Ru(III) ionic solutions (using RuCl3·nH2O) in the
presence of a photoactivator. Metallic Ru particles
(1.3 nm average diameter) were obtained in the presence of benzophenone, although mixtures of partly
oxidised Ru particles and metallic Ru particles were
produced in the presence of benzoin.
MEAs were prepared using PtRu black and 60 wt.%
Pt/C as their anode and cathode catalysts, respectively. The cathode catalyst layers were fabricated using
0.5, 1.0, 2.0 and 3.0 mg cm–2 of Pt. The performance
of the single cell that used Pt/C as the cathode catalyst was higher than a single cell that used Pt black;
this result was pronounced when highly concentrated
MeOH (> 2.0 M) was used as the fuel.
Platinum Metals Rev., 2008, 52, (4)
252
APPARATUS AND TECHNIQUE
CHEMISTRY
Determination of Alcohols Using a Ni–Pt Alloy
Amperometric Sensor
RuO2–TiO2 Mixed Oxides Prepared From the
Hydrolysis of the Metal Alkoxides
J.-J. HUANG, W.-S. HWANG, Y.-C. WENG and T.-C. CHOU, Thin
Solid Films, 2008, 516, (16), 5210–5216
J. R. OSMAN, J. A. CRAYSTON, A. PRATT and D. T. RICHENS, Mater.
Chem. Phys., 2008, 110, (2–3), 256–262
Ni-Pt films were electrodeposited on Au/Al2O3.
Electrodes with Ni:Pt atomic proportions of 100:0,
25:75, 70:30, 82:18 and 0:100 all have a linear relationship between response current and EtOH
concentration for 50–300 ppm EtOH in alkaline solutions. With increasing Pt content, the response time
was reduced and the sensitivity was decreased. The
sensor with 70 at.% Pt was most stable (9 weeks).
Ru alkoxide/Ti tetraethoxide mixtures were hydrolysed
to give gels and powders containing 30–40 mol% Ru.
Basic or neutral conditions gave powders consisting
of crystalline RuO2 nanoparticles (2–10 nm diameter)
embedded in a matrix of crystalline (anatase) and
amorphous TiO2. Acid hydrolysis conditions led to
gels containing smaller, amorphous RuO2 nanoparticles (1–3 nm). Acid or neutral hydrolysis of Ru
ethoxide gave samples with lower surface Ru:Ti ratios
compared to the bulk, which also contained more
low-valent Ru.
A Multi-Walled Carbon Nanotube/Palladium
Nanocomposite Prepared by a Facile Method for
the Detection of Methane at Room Temperature
Y. LI, H. WANG, Y. CHEN and M. YANG, Sens. Actuators B: Chem.,
2008, 132, (1), 155–158
A composite (1) of Pd and C MWNTs was prepared
by reducing their aqueous mixtures with NaBH4.
TEM and AFM were used to investigate the morphology of (1). The electrical responses of (1) to CH4
were measured at room temperature. (1) exhibited a
response magnitude of ~ 4.5% towards 2% CH4.
BIOMEDICAL AND DENTAL
Influence of the Spacer Length on the in Vitro
Anticancer Activity of Dinuclear Ruthenium–Arene
Compounds
M.-G. MENDOZA-FERRI, C. G. HARTINGER, R. E. EICHINGER, N.
STOLYAROVA, K. SEVERIN, M. A. JAKUPEC, A. A. NAZAROV and
B. K. KEPPLER, Organometallics, 2008, 27, (11), 2405–2407
The title complexes exhibited promising cytotoxic
effects in human cancer cells, which could be increased
to an IC50 of 0.29 μM by increasing the spacer length
between the metal centres. Cytotoxicity could be correlated with lipophilicity and H2O solubility.
1,12-Bis{chlorido[3-(oxo-κO)-2-methyl-4-pyridinonatoκO4](η6-p-isopropyltoluene)ruthenium}dodecane is
more active than chlorido[3-(oxo-κO)-2-methyl-4pyronato-κO4](η6-p-isopropyltoluene)ruthenium.
Novel Ru(II) Oximato Complexes with Silent Oxygen
Atom: Synthesis, Chemistry and Biological Activities
N. CHITRAPRIYA, V. MAHALINGAM, L. C. CHANNELS, M. ZELLER,
F. R. FRONCZEK and K. NATARAJAN, Inorg. Chim. Acta, 2008,
361, (9–10), 2841–2850
[Ru(CO)(EPh3)2(bhmh)] (E = P or As; H2bhmh =
benzoic acid (2-hydroxyimino-1-methyl-propylidene)hydrazide), [Ru(CO)(EPh3)2(ihmh)] (H2ihmh =
isonicotinic acid (2-hydroxyimino-1-methyl-propylidene)-hydrazide) and [Ru(CO)(EPh3)2(hhmh)] (H2hhmh
= 2-hydroxy-benzoic acid (2-hydroxyimino-1-methylpropylidene)-hydrazide) were prepared. The hydrazone
ligand coordinates through the N atoms of the imine and
oxime and the O atom of the amide. The N–OH moiety
of the oxime is deprotonated. Antibacterial activity and
DNA-binding ability of the complexes were investigated.
Platinum Metals Rev., 2008, 52, (4)
ELECTRICAL AND ELECTRONICS
Synthesis of Ru/Multiwalled Carbon Nanotubes by
Microemulsion for Electrochemical Supercapacitor
S. YAN, P. QU, H. WANG, T. TIAN and Z. XIAO, Mater. Res. Bull.,
2008, 43, (10), 2818–2824
Ru nanoparticles were prepared by H2O-in-oil
reverse microemulsion, and then anchored on C
MWNTs. EDX spectra confirmed the presence of Ru
oxide in the as-prepared composites after electrochemical oxidation. CV demonstrated that the specific
capacitance of deposited Ru oxide electrode was significantly greater than that of a C MWNTs electrode.
PHOTOCONVERSION
Phosphorescent Iridium(III) Complexes with
Nonconjugated Cyclometalated Ligands
Y.-H. SONG, Y.-C. CHIU, Y. CHI, Y.-M. CHENG, C.-H. LAI, P.-T.
CHOU, K.-T. WONG, M.-H. TSAI and C.-C. WU, Chem. Eur. J.,
2008, 14, (18), 5423–5434
Ir(III) complexes (1–4) with nonconjugated N-benzylpyrazole ligands exhibit blue phosphorescence
with yields of 5–45 % in degassed CH2Cl2. (1) showed
emission that was nearly true blue at 460 nm with a
lack of vibronic progression. (1) was used as the host
for the green-emitting Ir(ppy)3 dopant in an OLED.
REFINING AND RECOVERY
Synthesis of Highly Porous Chitosan Microspheres
Anchored with 1,2-Ethylenedisulfide Moiety for
the Recovery of Precious Metal Ions
Y. KANAI, T. OSHIMA and Y. BABA, Ind. Eng. Chem. Res., 2008,
47, (9), 3114–3120
Highly porous chitosan microspheres (EDSC) with
large pores anchoring 1,2-ethylenedisulfide as a ligand
were synthesised for perfusion chromatography by
means of an oil-in-H2O-in-oil emulsion method.
EDSC was found to be a selective adsorbent for
Pd(II), Au(III) and Pt(IV) over base metals in HCl.
The adsorbed Pd(II) was completely desorbed using
aqueous thiourea solution.
253
DOI: 10.1595/147106708X370880
NEW PATENTS
CATALYSIS – APPLIED AND
PHYSICAL ASPECTS
CATALYSIS – REACTIONS
Cationic Rhodium Complexes
ASTRAZENECA AB
World Appl. 2008/084,258
JOHNSON MATTHEY PLC
A cationic Rh complex can be synthesised by mixing a Rh-diolefin-1,3-diketonate compound and a P
ligand in a ketone solvent; mixing with an acid to
form a solution of the Rh complex; evaporating at
least part of the solvent; optionally treating with an
ether; and treating the resulting complex with an alcohol. The Rh complex may be recovered and used as a
catalyst, for example in hydrogenation reactions.
Palladium-Germanium Transalkylation Catalysts
U.S. Patent 7,378,364
UOP LLC
Alkylaromatic transalkylation catalysts containing
acidic molecular sieve, Pd and Ge are claimed to have
good activities and attenuate aromatic ring saturation
and lights co-production, provided that sufficient Pd is
present. Pd is 0.2–1 wt.% and the atomic ratio of Ge:Pd
is at least 0.9:1. The molecular seive has pore size ≥ 6 Å.
CATALYSIS – INDUSTRIAL PROCESS
Adhesive Silicone Composition
5-Fluoro-N-hydroxy-pyridine-2-carboxamidine
World Appl. 2008/054,284
The title compound (1) is synthesised by reacting 2bromo-5-fluoropyridine with a Pd source in the
presence of 1-1'-bis(diphenylphosphino)ferrocene
(DPPF) and acetate ions, then with a cyanide source
to give 5-fluoro-pyridine-2-carbonitrile (2). The Pd
source may be tris(dibenzylideneacetone)dipalladium(0) or Pd acetate. (2) is then reacted with ethanol
and hydroxylamine to produce (1).
Optically Active 2-Amino-1-phenylethanols
LONZA AG
World Appl. 2008/077,560
The title compounds or salts thereof are prepared by
asymmetric hydrogenation of the corresponding 2aminoacetophenones in the presence of a Ru complex
catalyst with a chiral phosphine ligand. The chiral
phosphine ligand may be a diphosphine, and the Ru
complex catalyst may also have a chiral diamine ligand.
EMISSIONS CONTROL
Catalyst for Purification of Exhaust Gas
EAST CHINA UNIV. SCI. TECHNOL.
World Appl. 2008/080,791
World Appl. 2008/086,662
A crosslinkable adhesive silicone composition with
short crosslinking time giving suitable mechanical
properties for use as an adhesive joint and for waterproofing a seam is claimed. The composition
includes: (a) a polyorganosiloxane with at least two
alkenyl groups, preferably C2–C6, linked to Si; (b) a
polyorganosiloxane crosslinking agent with at least
two H atoms linked to Si; (c) a metal catalyst, preferably Pt; and (d) a reinforcing mineral filler. There is
also a polyorganosiloxane gum containing 0.001–0.2
wt.% alkenyl group(s), preferably vinyl groups.
A close coupled three-way catalyst includes a support selected from cordierite honeycomb ceramic
materials having a pore volume of 0.25–0.35 ml g–1.
The coating layer contains a mixture of hexaaluminates, perovskite type composite oxides, CeO2-ZrO2
solid solutions, rare earth oxides, alumina, alkali earth
metals and zeolites having a high Si:Al ratio. The
active components are Pd-Rh, rare earth oxides and
transition metals in the hexaaluminates and perovskite
type composite oxides. The catalyst works for low
temperature oxidation of HC and reduction of NOx.
Silicone-Based Pressure-Sensitive Adhesive
Engine Exhaust Catalysts Containing Palladium-Gold
BLUESTAR SILICONES FRANCE
DOW CORNING TORAY CO LTD
World Appl. 2008/081,913
NANOSTELLAR INC
European Appl. 1,925,362
The title composition contains: (a) the condensation
reaction product of a diorganopolysiloxane having
silanol groups on both molecular terminals and two
or more Si-bonded alkenyl groups in side molecular
chains, with an organopolysiloxane resin having one
or more hydrolysable groups, in the presence of a catalyst; (b) an organohydrogenpolysiloxane; (c) a
diorganopolysiloxane having Si-bonded alkenyl
groups on both molecular terminals; (d) an
organopolysiloxane resin; and (e) a platinum catalyst.
A catalyst for cleaning engine exhaust is claimed to
have improved CO oxidation characteristics. The catalyst includes a first supported catalyst containing Pt,
Pt-Pd or Pt plus a promoter such as Bi. A second supported catalyst contains Pd and Au in the weight ratio
Pd:Au of ~ 0.5:1.0–1.0:0.5, preferably ~ 0.84:1.0. To
improve aged catalyst performance, the first and second supported catalysts are coated onto different
layers, zones or monoliths of the substrate.
Thermoneutral Oil Reforming Catalyst
MAZDA MOTOR CORP
T. INUI et
A catalyst system for exhaust gas purification
removes HC and CO from exhaust gas at engine start
when the exhaust gas temperature is low, particulates
which are collected by a filter, and NOx. An active O2
generating device, an oxidation catalyst, a particulate
filter and a Pt-Rh catalyst are arranged in this order
from the upstream side of the exhaust passage.
al.
U.S. Appl. 2008/0,152,572
A catalyst containing Ni, Ce2O3, La2O3, Pt, ZrO2,
Rh and Re can be used for the thermoneutral reforming of liquid hydrocarbon fuels to give synthesis gas
(H2, CO, CO2 and CH4). The catalyst contains (in
wt.%): 0.5–15 Ni, 0.5–10 Ce2O3, 0.5–5 La2O3, 0.1–2
Pt, 0.5–3 ZrO2, 0.1–2 Rh and 0.1–2 Re.
Platinum Metals Rev., 2008, 52, (4), 254–255
Exhaust Emission Control Device
Japanese Appl. 2008-075,638
254
FUEL CELLS
ELECTRICAL AND ELECTRONICS
Nanowire Supported Catalysts
Sealed Penetration for Lithium Battery
GM GLOBAL TECHNOL. OPERATIONS INC
COMMISSARIAT À L’ÉNERGIE ATOMIQUE
World Appl. 2008/070,482
U.S. Appl. 2008/0,118,831
A fuel cell electrode is formed from C fibres with
metal oxide or C-coated metal nanowires directly
grown on them, which carry deposited nanoparticles
of Pt, Pd, Rh or Ru catalyst material. The metal
oxide may be SnO2, TiO2 or WO3, alternatively the
C-coated metal may be Sn, Ti or W. The supported
catalysts can be used for an electrode in a PEM for a
H2/O2 fuel cell.
A glass-to-metal penetration for the electrical insulation between two poles of a Li battery includes glass
such as TA23 or Cabal 12 glass, a Pt-Ir pin containing
Pt:Ir in the weight ratio 90:10, and a body made from
SS304L stainless steel. The coefficient of thermal
expansion (CTE) of the pin is 8.7 × 10–6 ºC–1. The
glass has good resistance in organic electrolyte medium combined with Li salt and a CTE < 8.7 × 10–6 ºC–1.
Fuel Electrode Catalyst
Organic Memory Device
SANYO ELECTRIC CO LTD
Japanese Appl. 2008-091,102
An electrode catalyst is claimed to have improved CO
poisoning resistance. An electrode for an MEA is
formed by arranging an alloy catalyst layer containing
Pt, Ru and one or more of Co, Ni, Mo, Pb, Fe, W or
Cr; an alloy catalyst layer containing Pt-Ru; and a Ru
catalyst layer, in this order from the polyelectrolyte
membrane to the gas diffusion layer. The fuel for the
fuel cell system may be reformed gas or organic matter.
APPARATUS AND TECHNIQUE
Palladium Alloy Composite Membrane
J.-S. PARK et
al.
U.S. Appl. 2008/0,116,078
SAMSUNG ELECTRONICS CO LTD
U.S. Appl. 2008/0,146,802
An organic memory device includes a first electrode, an organic active layer which contains an Ir
organometallic compound and an electrically conductive polymer, and a second electrode. Advantages
claimed are rapid switching time, decreased operating
voltage, decreased fabrication costs, increased reliability and improved non-volatility. The Ir organometallic compound has a maximum emission wavelength of 450–550 nm.
Iridium Oxide Film for a Semiconductor Device
OKI ELECTRIC IND. CO LTD
Japanese Appl. 2008-075,134
The title composite for H2 separation includes an
optional first metal coating layer selected from Ag,
Ni, Cu, Ru or Mo, applied by an electroplating
process onto a porous support which is preferably
porous Ni; a Pd coating layer applied using a sputtering process; and a second metal coating layer,
preferably Cu. The second metal coating layer is
heat treated to form an alloy layer of Pd and the second metal.
An electrode includes an Ir oxide film with a metal
membrane formed on its surface. High adhesion is
claimed at the boundary between the films. The
electrode can be used in a dielectric capacitor for a
semiconductor device. The Ir film is formed by a
reactive sputtering method using an O2-containing
gas and an Ir target with film deposition temperature
of 275–400ºC and sputtering pressure of
0.69–1.09 Pa.
Nonlinear Optical Organic Single Crystal Formation
SURFACE COATINGS
FURUKAWA CO LTD
Japanese Appl. 2008-001,529
A single crystal of an organic substance such as 4dimethylamino-N-methyl-4-stilbazolium tosylate can
be formed on a Pt wire in a supersaturated solution
of the organic substance by cooling the supersaturated solution. The crystal nucleus is preferentially
generated on the surface of the Pt wire. Generation
of multiple nucleation points is suppressed and crystals can be grown at a low degree of supersaturation.
Sprayable Water-Base PGM-Containing Paint
GENERAL ELECTRIC CO
European Appl. 1,936,010
A Pt group metal containing layer can be deposited
on a substrate by spraying a H2O-based paint containing metallic Pt group metal powder, H2O and a
methyl cellulose binder. Heat can be applied to interdiffuse the Pt group metal containing layer.
Optionally an additional layer of NiAl may be applied
as an underlayer. The Pt group metal is ≥ 96 wt.% of
the paint composition exclusive of H2O and binder.
BIOMEDICAL AND DENTAL
Methods of Depositing a Ruthenium Film
Organometallic Compounds for Cancer Treatment
ASM GENITECH KOREA LTD
UNIV. NEUCHÂTEL
European Appl. 1,950,217
Novel organometallic compounds for photodynamic therapy against cancer include a central
porphyrin or phthalocyanine backbone with ligand
linkers coordinated to at least one transition metal
selected from Ru, Rh, Os, Ir or Fe, preferably Ru. A
preferred compound is a tetranuclear Ru(II) complex
such as [Ru4(η6-arene)4(TPP)Cl8] (TPP = 5,10,15,20tetra(4-pyridyl)porphyrin).
Platinum Metals Rev., 2008, 52, (4)
U.S. Appl. 2008/0,171,436
A Ru film can be deposited on a substrate by
applying deposition cycles of a Ru organometallic
compound gas; purging the reactor; supplying
RuO4 gas; and purging the reactor. Alternatively,
each cycle includes simultaneously supplying RuO4
and a reducing agent gas; purging; and supplying a
reducing agent gas. A high deposition rate is
claimed, with good step coverage over structures
which have a high aspect ratio.
255
NAME INDEX TO VOLUME 52
Page
Abd-El-Aziz,
A. S.
Abu-Reziq, R.
Acerbi, N.
Acres, G.
Adams, K. M.
Adamson, K.-A.
Adcock, P.
Aiello, I.
Aiyer, R. C.
Aladjem, A.
Aldrich-Wright,
J. R.
Alivisatos, A. P.
Allaert, B.
Alper, H.
Andersson, S.
Antunes, O. A.
Arends, I.
Arndt, A.
Ash, P.
Atanasoski, R.
46
56
222
19
251
123
15
58
201
121
98
57
124
56
125
124
83
58
205
201
Baba, Y.
253
Baidina, I. A.
126
Balcom, J.
18
Ballauff, M.
124
Balme, G.
174
Baranowski, B.
120
Barnard, C.
38, 110
Barteau, M. A.
251
Batcha Seneclauze,
J.
58
Baudoin, O.
175
Baylet, A.
226
Bedford, R.
111
Beletskaya, I. P. 56, 251
Bellusci, A.
58
Bent, S. F.
252
Beretta, A.
56
Bhushan, B.
202
Bion, N.
224
Birss, V. I.
126
Birtill, J.
229
Blomen, L.
14
Blume, R.
224
Bode, M.
13
Bond, G. C.
107
Borg, A.
126
Page
Bredesen, R.
Bucur, R.
Burch, R.
126
120
226
Cai, F.
56
Calvo, F.
107
Cameron, D. S.
12
Campagna, S.
58
Campbell, C. T.
57
Campesi, R.
201
Cao, C.-N.
202
Cao, F.
125
Carraher, Jr., C. E. 46
Carrettin, S.
226
Carson, N. A. P.
132
Carty, A. J.
58
Castellano, C.
134
Cate, D. M.
57
Cavallaro, S.
58
Cele, L. M.
124
Centi, G.
229
Cermák, J.
120
Chan, W. K.
47
Chang, F. Y.
200
Chang, S.-Y.
58
Chang, Z.
126
Channels, L. C.
253
Che, C.-M.
96
Chen, J. C.
200
Chen, J. G.
251
Chen, M.
126
Chen, P.
200
Chen, S.
57
Chen, W.
57
Chen, X.-Z.
163
Chen, Y.
57, 200, 253
Chen, Z.
200
Cheng, K. W.
47
Cheng, Y.-M.
58, 253
Chi, Y.
58, 253
Chiarello, G. L.
225
Chitrapriya, N.
253
Chiu, Y.-C.
253
Cho, Y.-H.
252
Choi, J.
252
Chou, P.-T.
58, 253
Chou, T.-C.
253
Clark, Jr., W. M.
200
Coelho, A. V.
124
Platinum Metals Rev., 2008, 52, (4), 256–258
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Colacot, T. J.
124, 172, 175
Connick, W. B.
202
Copping, B. W.
132
Corbos, E. C.
226
Corcoran, C.
200
Cornish, L. A.
241
52
Corti, C.
Coville, N. J.
124
Crayston, J. A.
253
Crispini, A.
58
Cuevas, F.
201
Dai, Q.
200
De Lima, P. G.
124
de Lucas-Consuegra,
A.
227
De Souza, A. L. F. 124
de Vries, J.
110
Debe, M. K.
201
Di Noto, V.
125
Dixneuf, P.
174
Doppelt, P.
126
Dragutan, I.
71, 157
Dragutan, V.
71, 157
Dunn, P.
110
Dyson, P. J.
98
Egerton, T. A.
Eggeler, G.
Eichinger, R. E.
Eisman, G. A.
El-Shall, M. S.
Elzanowska, H.
Enick, R.
Es-Souni, M.
202
241
253
252
107
126
58
125
Fan, H.
Fang, Y.
Faravelli, T.
Farmer, D. B.
Farrauto, R.
Farrell, N. P.
Filatov, E. Yu.
Flanagan, T. B.
Fricker, S. P.
Fronczek, F. R.
126
126
56
58
134
97
126
120
97
253
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Fu, G.
Fu, X.
Fujitani, T.
174
200
200
Gac, W.
124
Gadiou, R.
201
Gancs, L.
201
Garje, A. D.
201
Gauffier, A.
57
Gélin, P.
226
George, E. P.
252
Ghedini, M.
58
Ghiotti, G.
124
Glatzel, U.
48, 241
Godbert, N.
58
121
Goltsov, V. A.
Golunski, S. E.
249
Goodman, S. N.
200
Gordon, R. G.
58
Graham, G. W.
251
Granite, E. J.
144
Grasa, G. A.
124
Griffith, W. P.
114
Grönbeck, H.
226
Groppi, G.
56
Gross, S.
125
Grove, L. J.
202
Grubbs, R. H.
222
Grünert, W.
56
Grunwaldt, J.-D.
225
Gulari, E.
56
Guryev, Yu. V.
56
Gushchin, A. V.
124
Gustafsson, K.
125
Habouti, S.
125
Habtemariam, A.
97
Haghighat, F.
125
Hamada, H.
200
Hambley, T. W.
97
Haneda, M.
200
Hanefeld, U.
83
Harada, M.
125, 252
Haridoss, P.
125
Hartinger, C. G.
96, 253
He, L.-N.
56
He, P.
126
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He, Y.
200
Heatherly, L.
252
Hedley, G. J.
126
Heinzel, J.
16
Henry, C. R.
108
Hii, M.
112
Hirscher, M.
201
Hiyama, T.
174
Holwell, A. J.
243
Hou, P. Y.
57
Hou, S.-Q.
163
Hou, X.
125
Hou, Y.-Y.
202
Hu, F. P.
201
Hu, J.-M.
202
Huang, C.
126
Huang, H. 57, 200, 252
Huang, J.-J.
253
Hung, J.-Y.
58
Hutchings, G. J.
108, 226
Hwang, S.-H.
47
Hwang, W.-S.
253
Hyakutake, T.
201
Hyde, T.
129
Ikushima, Y.
Ilinich, O.
Inukai, J.
Ioannides, T.
Ishigami, Y.
Itami, K.
Ivanova, I. I.
Iyoha, O.
124
134
201
124
201
251
56
58
Jakupec, M. A.
Jang, J. H.
Janiak, T.
Jenkins, J. W.
Jennings, Z.
Jiang, X.
Jin, G.-X.
Johansson, M.
Johnson, T.
Jones, C. J.
Jones, S.
253
18
200
249
14
252
251
224
23
21
100
Kanai, Y.
Kanar, N.
253
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Kandasamy, K.
Karlberg, G. S.
Kartopu, G.
Kasem, K. K.
Kashin, A. N.
Kato, K.
Kavitha, J.
Kawanami, H.
Kawi, S.
Kayama, T.
Keane, M. A.
Kempe, R.
Keppler, B. K.
Khodadadi, A.
Khokhlov, A. R.
Khotina, I. A.
Kiely, C. J.
Killimeyer, R.
Kim, I. J.
Kim, J.
Kim, S.
Kim, Y. K.
Kim, Y. S.
Kimura, Y.
Kirschning, A.
Kitagawa, H.
Kizaki, Y.
Klette, H.
Kobayashi, H.
Kobayashi, T.
Koermer, G.
Korenev, S. V.
Kraft, A.
Krause, J. A.
Krishnan, L.
Kubota, Y.
Kudo, A.
Kumar, K. S.
120
125
125
100
251
201
58
124
200
56
56
124
253
125
56, 251
251
108
58
202
57
57
202
202
125
251
201
56
126
201
201
134
126
177
202
252
201
227
125
Laffont-Dantras, L.
Lai, C.-H.
Laing, M.
Lanza, S.
Lapeña Rey, N.
Latroche, M.
Lautenschlager, H.
Lavina, S.
Ledoux, N.
Lee, E. P.
Lee, G.-H.
Platinum Metals Rev., 2008, 52, (4)
84
253
247
58
16
201
244
125
124
57
58
Page
Lee, W.
252
Leiva, E. P. M.
107
Leroy, E.
201
Leung, S.-K.
202
120
Lewis, F. A.
Li, C.
201
Li, D.
200
Li, E. Y.
58
Li, F.
126
Li, H.
58
Li, L.
126
Li, P.
200
Li, W.
200
Li, Y.
201, 253
Lin, X.
58
Lin, Y.
58
Liu, C. T.
252
Liu, M.
201
Liu, W.-P.
163
Liu, Y.
134, 252
Liu, Z.
126
Livi, M.
124
Lo, K. K.-W.
202
Lou, L.-G.
163
Lu, L.
252
Lu, Y.
124
Luan, W.
57
Lucas, M. F. A.
126
Lunin, V. V.
56
Machocki, A.
MacLachlan, M. J.
Macquarrie, D.
Maerz, J. J.
Maestri, M.
Mahalingam, V.
Mallick, K.
Malysheva, Y. B.
Manners, I.
Maruyama, K.
Mathiyarasu, J.
Mattinson, J. A.
Mazzolai, F.
McLean, G.
McPherson, J.
Meek, G.
Meggers, E.
Mei, Y.
Mejdell, A. L.
Mendoza-Ferri,
M.-G.
124
46
83
52
56
253
46
124
46
241
57
202
120
17
226
111
97
124
126
253
Page
Meng, X.
Mennecke, K.
Merki, D.
Miasek, E.
Middelman, E.
Milhano, C.
Miller, A.
Mimura, N.
Miyatake, K.
Moini, A.
Mondal, K. C.
Morandi, S.
Morreale, B.
Morris, S. E.
Mortazavi, Y.
Motohiro, T.
Mottet, C.
251
251
200
126
14
202
16
227
201
134
124
124
58
252
125
56
108
Nagumo, Y.
Narayanan, S. R.
Nastasi, F.
Natarajan, K.
Nazarov, A. A.
Negishi, E.
Negro, E.
Newkome, G. R.
Nishide, H.
Nogami, M.
Nørskov, J. K.
Noyori, R.
201
201
58
253
253
172
125
47
201
57
223
251
Ohriner, E. K. 186, 252
Okumura, K.
56
Oliver, A. G.
202
Orvig, C.
96
Oshima, T.
253
Osman, J. R.
253
Owston, N.
113
Ozkaya, D.
61
Pacchioni, G.
Pace, G.
Palacio, M.
Palmeri, N.
Panfilov, P.
Park, H.-S.
Park, I.-S.
Pashkova, A.
Pastor, G. M.
223
125
202
58
242
252
252
227
108
257
Page
Paul, M.
225
Pavelka, M.
126
Peng, Z.
57
Pérez-Tijerina, E.
108
Perutz, R.
96
Phani, K. L. N.
57
Pittman, Jr., C. U.
46
Pitts, M. R.
64
Pizzaro, D.
14
Pletcher, D.
202
Poizot, P.
84
Pollock, T. M.
125
Post, M.
56
Potter, R. J.
155
Pratt, A.
253
Presto, A. A.
144
Preußner, J.
48, 241
Prinetto, F.
124
Prins, S. N.
48
Prinz, F. B.
252
Proch, S.
124
Pugliese, T.
58
Puntoriero, F.
58
Qazi, A.
Qi, Y.
Qu, P.
112
57
253
Ramachandran, A.
Reedijk, J.
Reinecke, H.
Retailleau, P.
Revere, A.
Richens, D. T.
Rider, D. A.
Rostrup-Nielsen, J.
Ruseckas, A.
Russo, N.
Ryberg, P.
126
2
18
58
52
253
46
12
126
126
251
Sadler, P. J.
21, 97
Saiz, E.
57
Sakamoto, Y.
56, 120
Samuel, I. D. W.
126
Scerri, E. R.
247
Schauermann, S.
224
Schlichter, K.
244
Schofield, E.
222
Seo, J. H.
202
Page
Sermon, P. A.
Seshadri, S. K.
Setsune, J.
Severin, K.
Seymour, R.
Sheldon, R. A.
Shen, P. K.
Shen, W.
Shinjoh, H.
Shipman, P. O.
Shubin, Yu. V.
Simonet, J.
Skea, J.
Skoplyak, O.
Smith, M. B.
Solodenko, W.
Somorjai, G. A.
Song, Y.-H.
Spadoni, C.
Stasinska, B.
Stockdale, G. W.
Stolyarova, N.
Su, Q.
Sudo, T.
Sultana, A.
Sun, S.
Sun, X.-J.
Sung, Y.-E.
Susu, A. A.
Suzuki, A.
108
125
202
253
231
83
201
224
56
46
126
84
13
251
215
251
57
253
222
124
200
253
163
251
200
57
202
252
251
172
Tada, M.
Tai, Y.-C.
Takahashi, S.
Takahashi, T.
Takata, M.
Tamao, K.
Tanaka, A.
Tang, G.-R.
Tang, M.-C.
Tarasenko, E. A.
Terada, Y.
Theis, J. R.
Thomas, Sir J. M.
Thompsett, D.
Thornback, J. R.
Thurier, C.
Tian, T.
Toda, M.
Tompos, A.
Tomsia, A. P.
227
201
252
172
201
173
201
251
202
56
208
56
108
108
21
126
253
202
225
57
Platinum Metals Rev., 2008, 52, (4)
Page
Tong, X.-Q.
Topsøe, H.
Torker, S.
Tromp, M.
Tronconi, E.
Tsai, M.-H.
Tsiouvaras, N.
Tu, S.-T.
Turner, G.
Tysoe, W. T.
Tyurin, V. S.
120
12
200
108
56
253
227
57
112
224
56
Ubbelohde, A. R.
Ueji, M.
Ueno, F.
Uma, T.
120
125
17
57
Vaccari, A.
124
Valdez, T. I.
201
van Bokhoven, J. A. 223
van den Berg,
M. W. E.
56
van Dokkum, J.
13
van Santen, R. A.
229
Venkataramanan,
N. S.
124
Verpoort, F.
124
Vigny, H.
245
Visart de Bocarmé,
T.
223
Vix-Guterl, C.
201
Vlassak, J.
58
Völkl, R.
48, 241, 242
Wang, D.
56
Wang, E.
56
Wang, H.
200, 253
Wang, J.-Q.
56
Wang, X.
124
Wang, Y.
57
Wang, Y.-M.
163
Wang, Z.
201
Wardell, J. L.
124
Watanabe, M.
201
Wells, P.
108
Wenderoth, M.
48
Weng, Y.-C.
253
Weston, M.
14
Wey, M. Y.
200
Page
Whitacre, J. F.
201
Whiting, A.
112
Wicke, E.
121
Wickleder, M. S.
58
Wicks, M.
12
Wieckowski, A.
201
Wilkie, J.
14
Witcomb, M. J.
124
253
Wong, K.-T.
Wrzesniok-Rossbach,
W.
244
Wu, C.-C.
253
Wu, X.
113, 200
Xia, Y.
Xiao, J.
Xiao, Z.
Xiong, G.
Xu, H.
57
200
253
57
57, 125, 252
Yamauchi, M.
Yan, S.
Yanagisawa, S.
Yang, H.
Yang, M.
Yang, S.
Yang, Y.-P.
Yates, J. T.
Ye, Q.-S.
Yersin, H.
Yi, T.
Yin, Y.
Yoshida, T.
Yu, M.
Yu, Y.
Yusenko, K. V.
201
253
251
57
253
200
163
57
163
155
126
57
202
126
163
126
Zadesenets, A. V.
Zeller, M.
Zhang, J.
Zhang, J.-Q.
Zhang, K. Y.
Zhang, X.
Zhao, K.
Zhao, Q.
Zheng, S.
Zhu, S.
Zhu, X.
Ziessel, R.
126
253
57
202
202
201
126
126
201
252
58
58
258
SUBJECT INDEX TO VOLUME 52
Page
a = abstract
AFM Probes, Pt, Pt-Ir, Pt-Ni, coated, a
202
Alcohols, EtOH, sensors, a
253
MeOH, decomposition
222
fuel
12, 134
oxidation
125, 222
steam reforming
134, 222
for synthesis of amides
110
Aldehydes, by hydroformylation
110
hydrogenation
110
reduction, a
200
unsaturated, hydrogenation, selective, a
56
Alkanes, conversions
107
Alkenes, C–C coupling
38
Alkyl Halides, one-electron cleavage of C–Br, C–I
84
Alkynes, C–C coupling
38
carbonylation
215
hydrogenation, selective, a
56
Amides, synthesis
110
Amines, secondary, tertiary, by hydroaminomethylation 110
for synthesis of amides
110
Aminocarbonylation, aryl halides
110
Apparatus and Technique, a
57–58, 125–126, 201, 253
Arenes, + iodoarenes, coupling reactions, a
251
Aryl Halides, reactions 38, 56, 110, 124, 172, 200, 215, 251
Arylation
110, 124
Arylboronic Acids, reactions
110, 251
Biaryls, synthesis
110
Biological Activity, Ru(II) oximato complexes, a
253
Biological Probes, luminescent, Ir(III)-polypyridines, a 202
Biomedical and Dental, a
126, 253
Biosensors, DNA, a
126
Book Reviews, “Adventures at the Bench”
52
“Catalysis for Renewables”
229
“Frontiers in Transition Metal-Containing Polymers” 46
“Green Chemistry and Catalysis”
83
“Highly Efficient OLEDs with Phosphorescent
Materials”
155
“Medicinal Applications of Coordination Chemistry” 21
“The Periodic Table: Its Story and Its Significance”
247
Boranes, C–C coupling
38
Boronates, C–C coupling
38
Boronic Acids, C–C coupling
38
Boronic Esters, C–C coupling
38
CALPHAD, Cr-Pt
241
Cancer, anti-, agents, aminoalcohol-Pt complexes
96
azido-Pt(IV) complexes
2
azolato-bridged dinuclear Pt compounds
2
BBR3464
21
bis(azpy)Ru(II)
2
di-Pt complexes
21
dinuclear cationic species containing Ru(II) and Pt(II) 2
dinuclear Ru-arenes, a
253
KP1019
96
NAMI-A
2, 96
Pd complexes
21
Pt chxn
96
Pt(II), Pt(IV) complexes
96
Rh complexes
21
Ru complexes
21
Ru organometallics
96
Ru quinonediimines
96
Ru(II), Ru(III), Ru(IV) complexes
96
[Ru(sandwich)(diamine)Cl]
2
tri-Pt complexes
21
drugs, carboplatin
2, 96, 126, 163
cisplatin
2, 21, 96, 163
Platinum Metals Rev., 2008, 52, (4), 259–266
Page
Cancer, (cont.)
eptaplatin
163
iproplatin
96
lobaplatin
163
nedaplatin
163
oxaliplatin
2, 163
picoplatin
96, 163
satraplatin
2, 96, 163
Carbenes
38, 71, 200
Carbon, catalyst support, Pt/C, TEM
61
Carbon Oxides, CO, addition, H–D exchange reaction 222
combustion, a
56
from glycerol, a
251
+ NO
107
oxidation
56, 222
for reduction, of NO, a
200
sensors
201, 215
transport, through [email protected] nanoparticles, a
57
CO2, supercritical, hydrogenation, + HN(CH3)2
215
solvent, a
56
Carbonylation, alkynes
215
Carboxylic Acids, for synthesis of amides
110
Catalysis, Applied and
Physical Aspects, a
56, 124, 200, 251
asymmetric
110
book reviews
83, 229
conferences
110, 172, 222, 229
in green chemistry
83, 110
Industrial Process, a
56, 200, 251
microwave heating
64
Reactions, a
56, 124, 200, 251
for renewables
229
Catalysts, analysis, Pt
205
encapsulated
64
nanoalloys
107
pgm, fundamental studies
249
pgm/support, 2D mapping
222
recycling
56, 64, 71, 157, 215, 251
supported, analysis, crystallite size, by XRD
129
particle size, by TEM
61
temperature-programmed reduction
249
Catalysts, Iridium, H–D exchange reaction; + CO
222
hydrogenation
229
Ir/CeO2, steam reforming of EtOH
222
Catalysts, Iridium Complexes, amides, from alcohols 110
half-sandwich Ir(III) hydroxyindanimines, ROMP of
norbornene, a
251
vinyl polymerisation of norbornene, a
251
intermolecular enantioselective hydroamination
110
Ir-N-tosyldiamines, aldehyde reduction, in H2O, a
200
monotosylated ethylenediamine Ir(III), hydrogenation 110
Catalysts, Osmium Complexes, Os EnCat 40
64
Catalysts, Palladium, aqueous reforming
229
dehydrogenation
229
electrocatalysts, CuPd, a
202
Ni-Pd, anodes, for DMFCs, a
125
Pd/hollow C spheres, for DAFCs, a
201
Pd/Vulcan XC-72 C, for DAFCs, a
201
Pd-Co-Ag/C, -Au/C, -Pt/C, cathodes, for DMFCs, a 57
Pd-Co-CN, for PEFCs, a
125
H–D exchange reaction; + CO
222
hydrogenation
229
hydrogenolysis
229
oxidation
229
Pd(111), ethene + acetic acid
222
Pd(0) EnCat, microwave heating, hydrogenations
64
Pd(0) EnCat NP30, microwave, nitro reduction
64
transfer hydrogenation
64
Pd nanoparticles, Heck reactions
38
Pd tip of field ion microscope, H2 + NO
222
Pd/Al2O3 , + Co, Cu, Na, Ni, NO reduction/CO, a
200
combustion of natural gas
222
259
Page
Page
Catalysts, Palladium, (cont.)
dechlorination of PVC, a
56
MeOH steam reforming
134
124
oxidation of CH4, a
preparation, by flame-spray pyrolysis
222
total oxidation of CH4
222
Pd/(Al2O3 + MOx), oxidation of CH4, a
124
Pd/alumina beads, Hg oxidation
144
Pd/BaSO4, Stille cross-couplings, a
124
Pd/C, o-chlorotoluene hydrogenolysis, a
200
Heck reactions
38
Pd/C microspheres, hydrogenation of ethylene, a
124
Pd/LaCoO3(flame-spray pyrolysis), NO reduction/H2 222
Pd/LaCoO3(impregnation), NO reduction/H2
222
Pd/(La0.2Sr0.3Ba0.5)(MnAl11)O19, natural gas combustion 222
Pd/membrane, synthesis of H2O2
222
Pd/YSZ, natural gas combustion
222
Pd nanoparticles/Celite®, Heck reactions
38
Pd nanoparticles/spherical polyelectrolyte brushes, a 124
PdO/support, natural gas combustion
222
Pd particles/Fe2O3 film/Pt(111), MeOH decomposition 222
PdAu, ethene + acetic acid
222
Pd-Ag/membrane, synthesis of H2O2
222
Pd-Au/Al2O3, selective oxidation of styrene, a
124
PdAu/Al2O3, /C, /TiO2, H2O2 synthesis
107
PdRh/γ-Al2O3, NO-CO reaction
107
‘Pd-Zn/oxide support’, mechanical strength
134
MeOH steam reforming
134
‘Pd-ZnO/Al2O3’, MeOH steam reforming
134
Catalysts, Palladium Complexes, aminocarbonylation
of aryl halides, synthesis of amides
110
biaryl synthesis
110
+ bidentate phosphines, dippb, dppe, Heck reactions
38
+ Buchwald ligands, Suzuki couplings
172
+ Buchwald ligands, Suzuki-Miyaura reactions
38
C–C bond forming
83
C–C coupling
38
C–H activation
110, 172
C-5 arylation of thiazoles
110
carbene complexes, Heck reactions
38
3
3
Csp –Csp coupling
172
cyclisation of 2-substituted halogenoarenes
110
‘cyclo-functionalising’ unactivated C–C multiple
bonds
172
1,6-diene Pd(0) monophosphine, Suzuki-Miyaura
reactions
38
DPEphosPdCl2, organozinc-based transformations
172
dppfPdCl2, organozinc-based transformations
172
Suzuki couplings
172
dtbpfPdCl2, coupling reactions
172
(DtBPF)PdX2, α-arylation of ketones, a
124
enantioselective –OH addition, in cyclisation
110
Hiyama couplings
172
homogeneous telomerisation
229
intermolecular enantioselective hydroamination
110
Kumada couplings
172
+ N-heterocyclic carbenes, Kumada reactions
38
Stille reactions
38
Suzuki-Miyaura reactions
38
oxime-based palladacycle/composite, C–C coupling, a 251
palladacycle complexes, Heck reactions
38
Suzuki-Miyaura reactions
38
+ PCy3, Stille reactions
38
Suzuki-Miyaura reactions
38
Pd(II) acetate, vinylic substitution reactions, aryl
halides
38
t
[PdBr(P(
Bu)3)]2, Suzuki-Miyaura reactions
38
t
Pd( Bu3P)2, organozinc-based transformations
172
Suzuki couplings
172
[PdCl(η3-C3H5)]2, Hiyama reactions
38
PdCl(CH2Ph)(PPh3)2, Stille reactions
38
PdCl2/CuCl, scCO2/PEG, aerobic oxidation, styrene, a 56
PdCl2(dppf), Kumada reactions
38
PdCl2(PhCN)
38
2, Sonogashira reactions
i
PdCl2(P( Pr)3)2, Hiyama reactions
38
Catalysts, Palladium Complexes, (cont.)
PdCl2(PPh3)2, Negishi reactions
38
Sonogashira reactions
38
38
Pd2dba3 + IMes·HCl, Suzuki-Miyaura reactions
Pd2(dba)3 + IPr·HCl, Kumada reactions
38
Pd2dba3 + IPr·t HCl, Suzuki-Miyaura reactions
38
Pd(dba)2 + P( Bu)3, cyanation of aryl bromides, a
251
Pd diphosphine dendrimer/SiO2, intramolecular
cyclocarbonylation of iodinated aryl amines
215
Pd/dppf-based, Negishi reactions
38
Pd EnCat, microwave, cross-coupling reactions
64
Pd EnCat 30, microwave, cross-coupling reactions
64
Pd EnCat polyTPP30, microwave, cross-couplings
64
Pd(II) + ethylphosphatrioxaadamantane/SiO2, Suzuki
coupling
110
Pd nanoparticles, stabilised by polymer micelles,
Suzuki-Miyaura cross-coupling, a
251
Pd(OAc)2, olefins + aryl halides
38
Pd(OAc)2 + IPr·HCl, Stille reactions
38
Pd(OAc)2/Cy3P, Suzuki coupling
172
Pd(OAc)2/PPh3, Heck reactions
38
Pd P–C–N–C–P diphosphine/SiO2, carbonylative
cross-couplings
215
t
Pd(P( Bu)3)2, Negishi reactions
38
Stille reactions
38
Pd(Ph3P)4, Suzuki couplings
172
synthesis of tetradecane
172
Pd(PPh3)4, Kumada reactions
38
Stille reactions
38
Suzuki-Miyaura reactions
38
Pd(II) phosphine, Suzuki couplings
215
Pd4 phosphine metallodendrimer, Suzuki couplings
215
Pd(II) salts + diphenyl-2-pyridylphosphine, alkyne
carbonylation
215
Pd(II) with S donors/SiO2, Suzuki coupling
110
Pd/poly(N-vinylimidazole), Mizoroki-Heck reaction, a 56
Pd/poly(N-vinylimidazole-co-N-vinylcaprolactam),
Mizoroki-Heck reaction, a
56
phosphine-ArgoGel-Pd, Suzuki-Miyaura couplings
215
pincer
complexes, Heck reactions
38
t
+ P( Bu)3, Heck reactions
38
Stille reactions
38
Suzuki-Miyaura reactions
38
Q-Phos based FibreCat, coupling reactions
172
Suzuki coupling, in synthesis of palytoxin
172
Suzuki-Miyaura reactions
110
Catalysts, Platinum, aqueous reforming
229
BaO(100)/Pt(100), absorption of NO2
222
electrocatalysis
229
electrocatalysts, FePt, formic acid electrooxidation, a 57
Pd-Co-Pt nanoparticles/C, cathodes, for DMFCs, a 57
platinised C, cathodes, for fuel cells, microchips
12
Pt, nanostructured thin film, a
201
for PAFCs
12
for PEMFCs
12, 201
for SOFCs, a
252
Pt black, cathodes, for DMFCs, a
252
electrodes, for PEMs, a
252
Pt/C, aged, SAXS, TEM, XRD
129
cathodes, for DMFCs, a
252
O2 reduction reaction, mechanism
222
electrodes, in H2/O2 fuel cells, a
57
modified by CeO2, cathodes, for PEMFCs, a
125
Pt/GNFs, for PEMFCs, a
252
Pt/XC-72, for PEMFCs, a
252
Pt3Cr nanoalloy, for fuel cells
107
PtNiFe, Pt59Ni39Fe2, nanostructured thin film, a
201
PtNiZr, for PEMFCs, a
201
PtRu, see Catalysts, Ruthenium
green rusts(Pt), dechlorination, tetrachloroethylene, a 252
H–D exchange reaction; + CO
222
hydrogenation
229
Ni-Pt-Pt(111), glycerol reforming, a
251
oxidation
229
Pt, diesel oxidation catalyst
23
Platinum Metals Rev., 2008, 52, (4)
260
Page
Catalysts, Platinum, (cont.)
diesel particulate filter
selective catalytic reduction, NOx control
Pt(111), glycerol reforming, a
Pt(0) EnCat, microwave, hydrogenations, reductions
Pt(0) EnCat 40, microwave, hydrogenations
Pt nanoparticles, encapsulated in hollow metal oxide
spheres, CO oxidation
Pt tip of field ion microscope, H2 + NO
Pt/activated C fibre cloth, H2 sensor, a
Pt/Al2O3, preparation, by flame-spray pyrolysis
sintered, n-heptane reforming, a
total oxidation of CH4
Pt/β-Al2O3 + K+, combustion of propane
Pt/alumina beads, Hg oxidation
Pt–Al2O3/Si, NO + H2, a
Pt-Ba/Al2O3, Pt-Ba-Ce/Al2O3, NOx trap, a
Pt/Ba/γ-alumina, NOx storage
Pt/K/Al2O3, lean NOx trap, CO oxidation, a
Pt/C, particle size analysis, by TEM
Pt/ceria-containing supports, > 800ºC, redispersion
Pt/Cu–Mg(Al)O, NOx storage, a
Pt–Mg(Al)O, NOx storage, a
Pt/SiO2 filter, for TiO2-based O2 sensor, a
Pt/TiO2, degradation of dichloroacetate anion, UV, a
visible light, a
Pt/TiO2–xNx, degradation of VOCs, visible light, a
Pt/zeolites, NO reduction, with diesel, a
Pt nanoparticles/magnetite nanoparticles, selective
hydrogenation, a
PtAu, PtSn, nanoparticles, alkane conversions
Pt-Ni-Pt(111), glycerol reforming, a
Pt-Pd-Au/CeO2, total oxidation of CH4
Pt-Re/Al2O3, metal segregation, a
sintered, n-heptane reforming, a
Pt-Rh/Al2O3, preparation, by flame-spray pyrolysis
total oxidation of CH4
Pt-Ru/Al2O3, preparation, by flame-spray pyrolysis
total oxidation of CH4
steam reforming
Catalysts, Platinum Complexes, Karstedt’s catalyst,
hydrosilylation, curing of silicones
Catalysts, Rhodium, H–D exchange reaction; + CO
hydrogenation
PdRh/γ-Al2O3, NO-CO reaction
Pt-Rh/Al2O3, preparation, by flame-spray pyrolysis
total oxidation of CH4
Rh/Al2O3, CO combustion, H2 combustion, a
preparation, by flame-spray pyrolysis
total oxidation of CH4
Rh/MgAl2O4/Al2O3, steam reforming of bioethanol
Ru/SiTiO3:Rh, solar H2 production
Catalysts, Rhodium Complexes, BINAPHOS,
enantioselective hydroformylation
BIPHEPHOS, hydroformylation
bisphosphine, asymmetric hydrogenation
diazaphospholane, enantioselective hydroformylation
Hiyama couplings
homogeneous hydrogenation
hydroaminomethylation of olefins SM
hydroformylation of olefins, LP Oxo Process
monophosphoramidite, asymmetric hydrogenation
phosphite, enantioselective hydroformylation
RhCl(CO){P[OCH(CF3)2]3}2, arenes + iodoarenes, a
RhCl(PPh3)3/dendritic SBA-15, hydroformylation, a
Wilkinson’s catalyst/dendritic SBA-15, a
Catalysts, Ruthenium, aqueous reforming
electrocatalysts, PtRu, nanostructured thin film, a
PtRu black, anodes, for DMFCs, a
PtRu/C, + Mo, for DMFCs
H–D exchange reaction; + CO
hydrogenation
oxidic Ru surfaces, oxidation of MeOH
Pt-Ru/Al2O3, preparation, by flame-spray pyrolysis
total oxidation of CH4
Platinum Metals Rev., 2008, 52, (4)
23
23
251
64
64
222
222
57
222
251
222
222
144
56
251
222
56
61
222
124
124
125
202
202
200
200
56
107
251
222
56
251
222
222
222
222
229
243
222
229
107
222
222
56
222
222
222
222
110
110
110
110
172
229
110
110
110
110
251
200
200
229
201
252
222
222
229
222
222
222
Page
Catalysts, Ruthenium, (cont.)
Ru nanoparticles/MgAl spinel, NH3 synthesis
222
Ru/SiTiO3:Rh, solar H2 production
222
RuSn/SiO2, cyclododecatriene selective hydrogenation 107
Catalysts, Ruthenium Complexes, amide preparation 110
C–C bond forming
83
Cp*Ru(COD)Cl, oxidation, regio-, stereoselective
172
F-containing polymer-bound Ru alkylidene, RCM
71
fluoro-tagged, first-generation Grubbs-Hoveyda
157
second-generation Grubbs-Hoveyda
157
Grubbs’ catalyst, conversion of seed oils
222
olefin metathesis
222
polymer-based phosphine resin scavengers
215
Hoveyda’s second-generation, RCM, to SB-462795, a 200
immobilised NHC Ru complex, CM, RCM
71
immobilised Ru benzylidene complex, RCM, dienes 157
self-metathesis, internal olefins
157
ionic liquid-tagged, NHC-Ru, PCy3-Ru
157
NHC Ru complex immobilised on monolithic support 71
oxidation
83
phosphine-ArgoGel-Ru(II), hydrogenation, of scCO2 215
polymer-bound NHC Ru complex, soluble, RCM
71
polystyrene-Ru-allenylidene, cyclisation of olefins
157
hydrogenation of olefins
157
RCM of olefins
157
Ru alkylidenes, immobilisation, via alkylidene ligands 71
via anionic ligands
157
via the arene ligand
157
via N-heterocyclic carbene ligands
71
via phosphane ligands
71
via the Schiff base ligand
157
tagged, fluoro, ionic liquid
157
Ru-based, H2O-soluble, metathesis, RCM, ROMP
71
Ru carbenes, metathesis, gas-phase, a
200
Ru O-hydroxyaryl-substituted NHCs, ROMP, a
124
Ru-pincer, synthesis of amides
110
supported NHC Ru complexes, RCM, ROM/CM
71
zeolite-supported, RCM
71
Chemistry, a
58, 126, 202, 253
Cisplatin
2, 21, 96, 163
Coatings, Ir, by CVD, EBVD, PVD
186
on Rh nozzles
186
IrO2, on DSA®, on Ti electrodes
177
IrO2/RuO2, on DSA®, on Ti electrodes
177
mixed Ir/Ru oxide, on Ti electrodes
177
Pt, on Ti electrodes
177
RuO2, on Ti electrodes
177
Coefficient of Thermal Expansion, Ir3X
208
Colloids, PVP-coated, Pd particles, Pt particles, a
125
Combustion, CO, H2, a
56
natural gas
222
propane
222
186
Composites, Ir-Y2O3 electrode
Pd nanoparticle/C template, a
201
Conferences, Catalysis for Renewables,
The Netherlands, 2006
229
Challenges in Catalysis for Pharmaceuticals and
Fine Chemicals, U.K., 2007
110
Creep 2008, Germany, 2008
241
Creep 2011, Japan, 2011
241
Cross Coupling and Organometallics, France, 2007
172
Dalton Discussion 10: Applications of Metals in
Medicine and Healthcare, U.K., 2007
96
EuropaCat VIII: “From Theory to Industrial
Practice”, Finland, 2007
222
EuropaCat IX: “Catalysis for a Sustainable World”,
Spain, 2009
222
Faraday Discussion 138: Nanoalloys – From
Theory to Applications, U.K., 2007
107
10th Grove Fuel Cell Symp., London, 2007
12
Copper, palladised
84
Coupling Reactions, arenes + iodoarenes, a
251
C–C
38, 124, 251
carbonylative
215
conference
172
261
Page
Page
Creep, conference
GTH, GTHR, oxide dispersion strengthened Pt alloys
Pt alloys
Pt-Al-Cr-Ru, by modelling
Pt-Rh
Ru-Ni-Al, ternary B2 alloys, a
Cross Metathesis, using immobilised Ru alkylidenes
Crucibles, Ir
CVD, Ir coatings
pulsed, Ru thin films, a
Cyanation, aryl bromides, a
Cyclisation, 2-substituted halogenoarenes
by enantioselective –OH addition
olefins
Cyclocarbonylation, intramolecular, iodinated aryl
amines
241
241
241
241
241
125
71
186
186
58
251
110
110
157
Dechlorination, PVC, a
tetrachloroethylene, a
Decomposition, MeOH
Deformation, plastic, Ir
Deposition, atomic layer deposition, Ru thin films, a
CVD, EBVD, PVD, Ir
Pd, on Cu substrate
pulsed CVD, Ru thin films, a
Deuterium, H–D exchange reaction
Diesel, emission control
heavy-duty engines, regulations; developments
light-duty engines, regulations; developments
NOx control
NOx traps, a
particulate matter control
for reduction, of NO, a
Diesel Oxidation Catalysts
Diesel Particulate Filters
Dihydroxylation, encapsulated catalyst, microwave
Disinfection, electrochemical, H2O
56
252
222
241
58
186
84
58
222
23
23
23
23
251
23
200
23
23
64
177
Films, Ir oxide/polyaniline composite, a
126
Ni-Pt, electrodeposition, on Au/Al2O3, a
253
Filters, Ir
186
‘Final Analysis’
61, 129, 205
Fine Chemicals, by catalysis
110, 172
Flue Gas, Hg oxidation
144
Formic Acid, electrooxidation, a
57
Fuel Cells, a
57, 125, 201, 252
catalysts, analysis by ICPES
205
222
Pt/C, O2 reduction reaction, mechanism
conference
12
DAFC, electrocatalysts, Pd/hollow C spheres, a
201
DMFC, catalysts
222
anodes, cathodes, a
252
conference
12
electrocatalysts, anodes, a
125
MeOH, fuel
134
nanocatalysts, cathodes, a
57
O distribution, visualisation, using a Pt porphyrin, a 201
electrocatalysts, nanostructured thin films, a
201
Pt/C, aged, XRD
129
Pt3Cr, O reduction activity
107
electrodes, conference
12
Pt/C, a
57
fuel, H2
12, 57, 134, 229
MeOH
12
“Fuel Cell Today Industry Review 2008”
123
membrane electrode assemblies, conference
12
PAFC, conference
12
PEFC, electrocatalysts, a
125
PEMFC, catalysts, high throughput study, a
201
conference
12
electrocatalysts, cathodes, a
125
graphite nanofibres as catalyst support, a
252
miniature, power source
134
portable applications
134
power, consumer electronics, large stationary
12
reformed MeOH, H2, fuel
134
SOFC, conference
12
current collector grid/patterned catalyst, by ALD, a 252
electrode/catalyst layer, by ALD, a
252
transport: airplane, locomotives, marine, road vehicles 12
Fuels, H2
12, 57, 134, 229, 249
hydrocarbons, a
57
MeOH
12, 134
215
Electrical and Electronics, a
202, 253
Electrochemistry, a
202
formation, IrOx/polyaniline composite films, a
126
H2O disinfection
177
measurements, Pt reference electrode
100
Electrodeposition, CuPd, a
202
Ir
186
Ni-Pt films, on Au/Al2O3, a
253
Pd nanowire arrays, a
125
Electrodes, Cu-Pd, disordered, cleavage, C–Br, C–I
84
modified, reduction, alkyl bromides, iodides
84
in fuel cells, see Fuel Cells
186
Ir-Y2O3 composite
IrO2-coated DSA®, free Cl2 production
177
IrO2-coated Ti, hypochlorite generation
177
lifetime
177
®
IrO2-type DSA , degradation, a
202
IrO2/RuO2-coated DSA®, free Cl2 production
177
IrO2/RuO2-coated Ti, hypochlorite generation
177
lifetime
177
micro-, Pt
100
mixed Ir/Ru oxide-coated Ti, in disinfection devices 177
Pd nanoparticles/MWCNTs/Nafion/GCE, a
126
platinised Ti electrodes, in disinfection device
177
Pt, electrochemical reference
100
Pt black, electroplated, human blood cell sensing, a
201
Pt-coated Ti electrodes, lifetime
177
Pt wire, electrochemical reference
100
reference, electrochemical, Pt wire
100
RuO2-coated Ti electrodes, lifetime
177
Emissions Control, a
56, 200, 251–252
catalysts, analysis by ICPES
205
diesel engines, heavy-duty, light-duty
23
Engines, heavy-duty diesel, light-duty diesel
23
Ethylene, hydrogenation, a
124
Platinum Metals Rev., 2008, 52, (4)
Gauze, Pt, Pt nanowire coating, a
Glycerol, reforming, a
Green Chemistry, catalysis
57
251
83, 110
Heck Reactions, Pd-catalysed
38
n-Heptane, reforming, a
251
Heterocycles, synthesis
110
High Temperature, ultra-, Ir3X, thermophysical prop. 208
High Throughput Screening Techniques
134, 201
History, Periodic Table
114, 247
HIV, anti-, Pt(II), Ru(II), Ru(III), Ru(IV) complexes
96
Hiyama Couplings
38, 172
TM
HotSpot Reactor, H2 generation
249
Human Blood Cells, sensor, a
201
Hydrides, Pd
120
Hydroamination, intermolecular, enantioselective
110
Hydroaminomethylation, olefins
110
Hydrocarbons, reforming
57, 249
Hydroformylation, enantioselective
110
olefins
110
styrene, a
200
Hydrogen, absorption
120, 201
combustion, a
56
diffusion coefficients, in Pd0.77Ag0.23
120
from bioethanol
222
from glycerol, a
251
from H2O
222
262
Page
Page
Hydrogen, (cont.)
from hydrocarbons, oxygenates
249
fuel
12, 57, 134, 229, 249
H–D exchange reaction
222
membranes
120, 126
+ NO
56, 222
sensors, a
57, 201
storage, Pd nanoparticle/C template composites, a
201
222
for synthesis of H2O2
uphill diffusion, ‘Lewis Effect’, Pd
120
Hydrogen Peroxide, synthesis
107, 222
Hydrogen Sulfide, + Pd, + Pd-Cu membranes, a
58
sensors
215
Hydrogenation, aldehydes
110, 200
asymmetric
110
encapsulated catalyst, microwave heating
64
ethylene, a
124
olefins
157
scCO2, + HN(CH3)2
215
selective, alkynes, a
56
cyclododecatriene
107
unsaturated aldehydes, a
56
transfer, aldehydes
110
encapsulated catalyst, microwave heating
64
Hydrogenolysis, o-chlorotoluene, a
200
Hydrolysis, Ru alkoxide/Ti tetraethoxide, a
253
Hydrosilylation, curing of silicones, Pt-catalysed
243
Hypochlorite, generation
177
Iridium Complexes, (cont.)
in OLEDs
155, 253
Ir(III) pyridylphosphines
215
Ir(III)/Au(I) phosphines
215
OLEDs
155, 202, 231, 253
Iridium Compounds, electrodes, see Electrodes
intermetallic, thermal conductivity, thermal expansion 208
Ir chloride solutions, for plating of Ir
186
Ir hexafluoride, for CVD
186
Ir oxide, in chemical refining of Ir
186
Ir oxide/polyaniline composite films, a
126
sodium hexabromoiridate(II) solutions, plating of Ir 186
ICPES, determination of Pt in solution
205
Ionic Liquids
38, 83
Iridium, coatings, by CVD, EBVD, PVD
186
on Rh nozzles
186
crucibles
186
deformation processing
186
deposition, electrodeposition
186
filters
186
Ir-Y2O3 composite electrode
186
joining
186
melting
186, 252
nanoparticles, a
126
Periodic Table
114, 247
plastic deformation
241
plating
186
powder metallurgy
186
processing
186
purification
186, 252
single crystals, deformation
241
sponge
186
welding
186
wire
186
Iridium Alloys, deformation processing
186
DOP-26
186
Ir-Pt, powder metallurgy
186
‘Ir-Nb’, dendritic segregation, a
252
‘Ir-Zr’, dendritic segregation, a
252
joining
186
melting
186
processing
186
Pt-Ir, coating, AFM probes, a
202
welding
186
Iridium Complexes, cyclometalated Ir(III)-polypyridines
in biological probes, luminescence, a
202
encapsulated Ir porphyrins, O2 sensors
46
Ir acetylacetonate, for CVD
186
Ir-allyl, for CVD
186
Ir(III) N-benzylpyrazoles, phosphorescence, a
253
Ir(btp)2(acac), in OLEDs
155
Ir-carbonyl, for CVD
186
Ir(COD)(MeCp), for CVD
186
Ir-cyclooctadienyl, for CVD
186
Ir(dfppy)2(pq), in OLEDs, a
202
Ir(ppy)2(DBM), Ir(ppy)2(SB), phosphorescence, a
126
Ir(ppy)3, luminescence, a
126
Platinum Metals Rev., 2008, 52, (4)
Jewellery, Pt, manufacture
Johnson Matthey, “Platinum 2007 Interim Review”
“Platinum 2008”
sustainability
Joining, Ir, Ir alloys
Kumada Couplings
52
54
198
132
186
38, 172
Lasers, Pt jewellery, manufacture
welding, Ir alloy
Lewis Effect, uphill diffusion of H, in Pd
Lipoid, with Pt(II) containing salicylate derivative
Lipophilicity, Pt(II) containing salicylate derivative
LPG, sensors, a
Luminescence, cyclometalated Ir(III)-polypyridines, a
dendritic tetranuclear Ru(II) complex
Ir(ppy)3, a
Pt(II) isoquinolinyl indazolates, a
Pt porphyrin, a
switching, Pt(II) dithiooxamides, a
52
186
120
163
163
201
202
46
126
58
201
58
Magnetism, nanoalloys, CoPt, CoRh, PdAu, PdFe,
PdNi, PtAu, PtFe, PtNi
107
Mannich Condensation, P-based, for aminophosphines 215
MEAs, conference
12
Medical Uses, pgm complexes, anti-HIV
96
anticancer
2, 21, 96, 126, 163
Melting, Ir, a
252
Ir alloys
186
Membranes, Pd, sulfidisation, a
58
Pd/modified α-Al2O3, in reactor, H2 production, a
57
Pd/Ag23%, heat treatment, a
126
Pd0.77Ag0.23, H2 diffusion coefficients, uphill effects
120
Pd-Cu, sulfidisation, a
58
Mercury, oxidation
144
Metal-Ligand Exchange Kinetics, Pt, Ru complexes
2
Metallodendrimers, encapsulated, Ir, Pd, Pt porphyrins 46
Metallurgy and Materials, a
57, 125, 201, 252
Metathesis, olefins
71, 157, 222
Methane, oxidation, a
124
sensors, a
253
total oxidation
222
Microwaves, in organic synthesis
38, 64
syntheses of cycloplatinated complexes, a
58
Mizoroki-Heck Reactions, a
56
Molten Salts, electrodeposition of Ir
186
Nanoalloys, CoPt, CoRh, PdAu, PdFe, PdNi, PdRh,
PtAu, Pt3Cr, PtFe, PtNi, PtSn
107
Nanocomposites, C MWNT/Pd, for detection of CH4, a 253
Pd nanoparticles-polyphenosafranine, nitrate sensing, a 58
Ru nanoparticles/C MWNT, for supercapacitor, a
253
Nanoparticles, FePt, a
57
Ir, a
126
Pd
38, 58, 124, 126, 201, 251
PdAu
107
Pd-Co-Ag, Pd-Co-Au, Pd-Co-Pt, a
57
263
Page
Page
Nanoparticles, (cont.)
Pd/Pt, a
201
Pt
56, 61, 222
[email protected], a
57
PtAu
107
PtSn
107
Ru
222, 253
253
RuO2, a
Nanostructures, yolk–shell, [email protected] nanoparticles, a
57
Nanowires, arrays, Pd, a
125
Pt, on metal gauze, a
57
Natural Gas, combustion
222
Natural Products, synthesis, by cross-coupling
172
Negishi Couplings
38, 172
Nitrite, sensors, a
58
Nitrogen, adsorption, on Pt(111), a
125
on Pt(111)(1×1)H, a
125
Nitrogen Oxides, NO, + CO
107
+ H2
56, 222
reduction, with CO, a
200
with diesel, a
200
NO2, adsorption
222
NOx, control
23
lean, trap
23, 56
selective catalytic reduction
23
storage, by catalysts
124, 222
traps, for diesel, a
251
Norbornene, ROMP, a
251
vinyl polymerisation, a
251
Palladium, (cont.)
uphill diffusion, ‘Lewis Effect’, H2
120
Palladium Alloys, absorption, H2
120
Cu-Pd, disordered, electrodes
84
modified, electrodes
84
CuPd, crystal structure information
84
electrocatalytic properties, a
202
electrodeposition, a
202
hydrides
120
membranes
58, 120, 126
nano-, PdAu, PdFe, PdNi, PdRh
107
PdAu nanoparticles, synthesis, in a sputter reactor
107
PdNi, PdZn, nanosized powders, a
126
Palladium Complexes, anticancer agents
21
dichloropalladium(II) ditertiary phosphines
215
dichloropalladium(II) pyridylphosphines
215
46
encapsulated Pd porphyrins, O2 sensors
OLEDs
155
organometallic polymers
46
[Pd]10[MTD]163, [Pd]50[MTD]113, complex-block
46
Pd(acac)2, decomposition, reduction, a
125
[Pd(NH3)4][Ni(Ox)2(H2O)2]·2H2O, thermal decomp., a 126
[Pd(NH3)4][Zn(Ox)2(H2O)2]·2H2O, thermal decomp., a 126
Pd oxoselenates, preparation, a
58
Pd(Se2O5), Pd(SeO3), Pd(SeO4), preparation, a
58
Ru2Pd phosphaadamantane
215
Palladium Compounds, K2PdCl4 in H2SO4 electrolyte, a125
Pd(II), recovery, with chitosan microspheres, a
253
PdCl2, in HCl, for Pd deposition
84
Pd(NO3)2, in HNO3, for Pd deposition
84
PdSO4·2H2O, in H2SO4, for Pd deposition
84
Particle Size Analysis, Pt/C catalysts, by TEM
61
Particulate Matter, control
23
Patents
59–60, 127–128, 203–204, 254–255
analysis
231
mapping
231
Periodic Table
114, 247
Pharmaceuticals, by catalysis
110, 172
Phase Diagrams, Cr-Ni-Pt
241
Cr-Pt
48
Pt-Al-Cr-Ni
48
Phases, Pt-Al-Cr-Ni
241
Phosphines, pgm complexes, applications, properties
215
Phosphorescence, electro-, Ir(dfppy)2(pq), in OLEDs, a 202
Ir(III) N-benzylpyrazoles, a
253
Ir(ppy)2(DBM), Ir(ppy)2(SB), a
126
Pt(II)–acetylides, a
58
Photocatalysis, degradation, of dichloroacetate anion, a 202
of VOCs, a
200
H2O, to H2
222
Photoconversion, a
58, 126, 202, 253
Photoreduction, Ru(III) ionic solutions, a
252
Plating, Ir
186
Platinum, additions, NiAl, wetting, of alumina, a
57
coating, AFM probes, a
202
colloidal particles, PVP-coated, a
125
Cr-Ni-Pt, phase diagram
241
Cr-Pt, CALPHAD
241
determination, in solution
205
doped, TiO2, O2 sensor, a
125
electrodes, see Electrodes
gauze, Pt nanowire coating, a
57
jewellery, manufacture
52
nanoparticles
56, 61, 201
nanowires, a
57
particles, particle size analysis, by TEM
61
Periodic Table
114, 247
phase diagrams
48
Pt(111), Pt(111)(1×1)H, adsorption of N2, a
125
Pt-Al-Cr
241
Pt-Al-Cr-Ni, phases
241
thermodynamic database
48
PtAl12Cr6, PtAl12Cr6Ni5, PtAl12Ni6
48
thin films, by OMCVD, a
126
Platinum Alloys, creep
241
Oils, seed, conversion
222
OLEDs
155, 202, 231, 253
Olefins, C–C couplings, a
124
cyclisation
157
Heck reactions
38
hydroformylation
110
hydrogenation
157
internal, self-metathesis
157
metathesis
71, 157, 222
RCM
157
OMCVD, Pt, precursor chemistry, processes, a
126
Organometallics, Pd
172
Organosilanes, cross-coupling
172
Osmium, Periodic Table
114 , 247
Osmium Complexes, OLEDs
155
organometallic polymers
46
Oxidation, aerobic, styrene, a
56
CH4, a
124
CO
222
electro-, formic acid, a
57
Hg
144
MeOH
125, 222
regio-, stereoselective, using Cp*Ru(COD)Cl
172
Ru catalysts
83
selective, styrene, a
124
222
total, CH4
Oxygen, sensors
46, 125
for synthesis of H2O2
222
Oxygenates, reforming
249
Palladium, absorption, H2
120
C MWNT/Pd nanocomposite, for detection of CH4, a 253
colloidal particles, PVP-coated, a
125
deposition, on Cu substrate
84
H2 storage
12
hydrides
120
membranes, a
57
nanoparticles
38, 58, 124, 126, 201
nanowire arrays, a
125
Pd nanoparticle/C template composites, a
201
Pd nanoparticles-polyphenosafranine, nitrate sensing, a 58
PdAu particles/Al2O3 film, by sequential condensation 107
Periodic Table
114, 247
Platinum Metals Rev., 2008, 52, (4)
264
Page
Page
Platinum Alloys, (cont.)
Ir-Pt, powder metallurgy
186
jewellery, manufacture
52
107
nano-, CoPt, PtAu, Pt3Cr, PtFe, PtNi, PtSn
Ni-Pt amperometric sensor, for alcohols, a
253
NiPtAl, wetting, of alumina, a
57
oxide dispersion strengthened, GTH, GTHR, creep
241
Pt-Al-Cr-Ru, creep properties, by modelling
241
Pt-Ir, Pt-Ni, coating, AFM probes, a
202
PtNi, PtZn, nanosized powders, a
126
Pt-Rh, creep
241
superalloys, Pt base
241
thermodynamic database
48
Platinum Complexes, anticancer agents, see Cancer
anticancer drugs, see Cancer
carbazole-based Pt(II)–acetylides, preparation, a
58
(cod)Pt(Me)2, for OMCVD, a
126
cycloplatinated complexes, synthesis, a
58
encapsulated Pt porphyrins, O2 sensors
46
EtCpPtMe3, MeCpPtMe3, for OMCVD, a
126
fluorene-based Pt(II)–acetylides, preparation, a
58
OLEDs
155
organometallic polymers
46
[Pt]50[MTD]113 complex-block
46
Pt(acac)2, decomposition, reduction, a
125
Pt(II) dithiooxamides, luminescence, switching, a
58
Pt(II) isoquinolinyl indazolates, luminescence, a
58
[Pt(Me2bzimpy)Cl](PF6)·DMF, vapochromic, a
202
[Pt(NH3)4][Ni(Ox)2(H2O)2]·2H2O, thermal decomp., a 126
[Pt(NH3)4][Zn(Ox)2(H2O)2]·2H2O, thermal decomp., a 126
Pt porphyrin, luminescence, a
201
Pt(II) pyridylphosphines
215
[Pt(R2-dto)2], + HCl, photoluminescence; + NH3, a
58
Ru2Pt phosphaadamantane
215
Platinum Compounds, anticancer agents, see Cancer
PtCl2 solution, dip coating, nano SnO2 thick films, a 201
Pt(II) salicylate derivatives, biological evaluation,
characterisation, design, lipophilicity,
liposomal formulation, synthesis
163
Pt(IV), recovery with chitosan microspheres, a
253
Platinum Group Metals, patents
231
Periodic Table
114, 247
Polymerisation, by metathesis
71, 124
vinyl-type, norbornene, a
251
Polymers, Ir oxide/polyaniline composite films, a
126
organometallic
46
PVC, dechlorination, a
56
PVP-coated, Pd, Pt, colloidal particles, a
125
PVP-protected, Ru particles, a
252
transition metal-containing
46
Powder Metallurgy, Ir, Ir alloys
186
Propane, combustion
222
PVD, Ir
186
Reforming, (cont.)
glycerol, a
251
n-heptane, a
251
hydrocarbons, a
57
steam, bioethanol, EtOH
222
MeOH
134
using HotSpotTM reactor, hydrocarbons, oxygenates 249
Release Liners, silicone
243
Renewables, catalysis
229
Rhodium, Periodic Table
114
Rhodium Alloys, nano-, CoRh, PdRh
107
Pt-Rh, creep
241
Rhodium Complexes, anticancer agents
21
OLEDs
155
Rh porphyrinoids, synthesis, dynamic structure, a
202
Rh(III) pyridylphosphines
215
ROMP, norbornene, a
251
Ru-based NHC-arene systems, a
124
using immobilised Ru alkylidenes
71
Ruthenium, Periodic Table
114
PVP-protected Ru particles, by photoreduction, a
252
Ru nanoparticles/C MWNTs, for supercapacitor, a
253
thin films, a
58
Ruthenium Alloys, Pt-Al-Cr-Ru, creep, modelling
241
Ru-Ni-Al, ternary B2, a
125
Ruthenium Complexes, anticancer agents, see Cancer
dendritic tetranuclear Ru(II) complex, luminescence
46
OLEDs
155
organometallic polymers
46
phosphine-ArgoGel-[Ru5C(CO)15], gas sensors
215
phosphine-ArgoGel-[Ru6C(CO)17]
215
Ru(II) oximato, preparation, biological activity, a
253
Ru(II) pyridylphosphines
215
Ru(II)/Au(I) phosphines
215
Ru2Pd phosphaadamantane, Ru2Pt phosphaadamantane 215
Ruthenium Compounds, bis(N,N'-di-tert-butylacetamidinato)Ru(II) dicarbonyl, deposition, a
58
electrodes, see Electrodes
RuCl3·nH2O, for photoreduction, a
252
RuO2 nanoparticles, a
253
RuO2-TiO2 mixed oxides, preparation, a
253
RCM, olefins
Ru carbene catalysts, a
synthesis, dicyclic compounds
macrocyclic compounds
SB-462795, a
using immobilised Ru alkylidenes
Reactors, membrane, H2 production, a
packed bed, Hg oxidation
Redox Systems, Pt reference electrode
Reduction, aldehydes, a
electrochemical, alkyl bromide, chlorides, iodides
NO, with CO, a
with diesel, a
with H2
temperature-programmed, catalytic materials
Refining, chemical, Ir
Refining and Recovery, a
Reformer, micro-, H2 production
Reforming, catalysts, metal segregation, a
ethylene glycol, EtOH, a
Platinum Metals Rev., 2008, 52, (4)
157
200
71
71
200
71
57
144
100
200
84
200
200
222
249
186
253
134
56
251
Scavengers, polymer-based phosphine resins
215
Selective Catalytic Reduction, NOx control
23
Self-Metathesis, internal olefins
157
Sensors, CH4, a
253
CO
201, 215
EtOH, a
253
H 2, a
57, 201
H 2S
215
human blood cells, a
201
LPG, a
201
nitrite, a
58
46, 125
O2
SO2
215
Silicones, Pt-catalysed hydrosilylation; release liners
243
Single Crystals, Ir, deformation
241
Soldering, Pt jewellery, manufacture
52
Solvent Extraction, Ir
186
Solvents, in catalysis
83, 110
Sonogashira Couplings
38, 64
Sponge, Ir
186
Sputtering, PdAu nanoparticles
107
Stille Couplings
38, 124
Styrene, hydroformylation, a
200
oxidation, aerobic, a
56
selective, a
124
Sulfidisation, Pd membranes, Pd-Cu membranes, a
58
Sulfur Oxides, SO2, sensors
215
Superalloys, Pt base
241
Pt-based, thermodynamic database
48
Supercapacitors, Ru nanoparticles/C MWNTs, a
253
Supercritical Fluids
38, 56
Surface Coatings, a
58, 126, 202
265
Page
Sustainability, Editorial
Suzuki Couplings
Suzuki-Miyaura Couplings
132
110, 172, 215
38, 110, 215, 251
TEM, Pt/C catalysts, particle size analysis
61
Temperature-Programmed Reduction, catalysts
249
Tetrachloroethylene, dechlorination, a
252
Thermal Conductivity, Ir3X (X = Hf, Nb, Ta, Ti, V, Zr) 208
Thermal Expansion, Ir3X (X = Hf, Nb, Ta, Ti, V, Zr) 208
Thermodynamic Database, Pt-based superalloys
48
Thermophysical Properties, Ir3X
208
Thiazoles, C-5 arylation
110
Thin Films, nanostructured, Pt, PtNiFe, PtRu, a
201
Ru, deposition, by atomic layer deposition, by CVD, a 58
Platinum Metals Rev., 2008, 52, (4)
Page
Ultrasound, in C–C couplings
38
Vapochromism, [Pt(Me2bzimpy)Cl](PF6)·DMF, a
VOCs, degradation, a
Water, electrochemical disinfection
solvent
Welding, Ir
Ir alloys
Wire, Ir
XRD, Pt/C catalysts, crystallite size analysis
202
200
177
110, 200, 251
186
186
186
129
266
Platinum Metals Review
Johnson Matthey Plc, Precious Metals Marketing, Orchard Road, Royston, Hertfordshire SG8 5HE, U.K.
E-mail: [email protected]
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