Full Text for Volume 48 Number 2 (April 2004)

This issue contains the following:

The Morphology of a Platinum/Ceramic Interface
Ceramics are attached to metals to confer additional properties. The ceramic is usually deposited by plasma technology which gives a join of high cohesive strength. However, the nature of the cohesion mechanism is unknown. Here, Peter Panfilov from Urals State University, Ekaterinburg, Russia; and Alexander Bochegov and Alexander Yermakov from the Ekaterinburg Non-Ferrous Metals Processing Plant, Russia, discuss the morphology of the transition layer at the interface between platinum (Pt) and alumina in alumina-coated Pt crucibles. These crucibles, mostly used for crystal growing, are able to withstand high temperatures and thermomechanical stress.

Manufacture of Platinum Fibre and Non-Woven Fabric
Fine Pt fibre, of diameter up to ~ 0.1 mm, has been produced by a wire drawing process by Tanaka Kikinzoku Kogyo K.K., Japan. Flocculate Pt fibre and non-woven fabric were made from the fibre. The background to this production is described by Kenya Mori from Tanaka. The Pt fibre and fabric are currently used as filtering materials in filtering applications that require both heat and chemical resistance, and as electrically conductive fillers for porcelain enamel.

Stabilising Palladium Colloids in Polymers
Colloids are particles of diameter ~ 1-1000 nm dispersed in a liquid, and thus have a very large surface area. Colloids need to be stabilised so they do not aggregate, and stability can be achieved through surface functionality using ligands, surfactants and polymers. Bénédicte Thiébaut, Johnson Matthey Technology Centre, Sonning Common, U.K., describes the preparation of Pd colloids stabilised with a non-ionic polymer, polyvinylpyrrolidone (PVP). There are interactions between hydrophobic segments of the polymer and the surface of the Pd colloid.

Developments towards Fuel Cell Vehicles
Philip D. Chizek, Ford Motor Company, Dearborn, U.S.A., describes Ford’s developments of: a hybrid vehicle that runs on either gasoline or battery electricity; a hydrogen hybrid vehicle with an internal combustion engine powered by hydrogen and boosted by a supercharger; and a vehicle that combines Ford’s hybrid technology with a hydrogen fuel cell. Professor Sinclair Gair, University of Strathclyde, Scotland, describes the Scottish Fuel Cell Consortium’s development of Scotland’s first fuel cell battery-powered electric vehicle.

Detecting Liquid Petroleum Gas (LPG) with Palladium Oxide
We briefly report work by scientists in India who have found the optimised number of Pd oxide catalyst layers to deposit, by a wet-chemical process, on a thin ZnO film for LPG detection. A sensitivity of 88% was observed for 1.6 vol.% LPG in air with a 15 second response and a 60 second recovery. The fast response and quick recovery provides a useful domestic LPG alarm.

Photoassisted Alkane Oxygenation by Ruthenium(II) Complex
The activation of the C-H bonds in saturated hydrocarbons is an important organic reaction. Now, researchers from Tokyo Metropolitan University, Japan, have been able to oxidise alkanes catalytically, by a stereospecific, photoregulated reaction, using chloro(Me₂SO)Ru(II) complexes with tris(2-pyridylmethyl)amine in the presence of 2,6-dichloropyridine N-oxide, under visible light irradiation. The Ru complex and irradiation were both necessary for oxidation to proceed. The reaction is thus photoassisted as the light regulates the reaction.

EuropaCat-VI: A Congress on Catalysis
The 6th European Congress on Catalysis held in Innsbruck, Austria, in September last year is reviewed by Reza Torbati, Johnson Matthey Technology Centre. His selective review covers heterogeneous catalysis work featuring the platinum group metals.

The Minting of Platinum Roubles in Russia (Parts I and II)
In Part I of a three part article, Professor Christoph J. Raub, former director of the Forschungsinstitut für Edelmetalle und Metallchemie, Schwäbisch-Gmünd, Germany, briefly describes the discovery of platinum in the Urals in the early 18th century, leading to the minting of platinum roubles. Over an eighteen year period 485,505 troy ounces of Pt were used for this. When the Pt price fell the coins were withdrawn from circulation. However, additional minting and other forgeries continued to be made. In Part II, David F. Lupton of W. C. Heraeus GmbH, Hanau, Germany, describes non-destructive tests on four Pt rouble coins and one coronation medallion to determine their composition. SQUID microscopy was used to study magnetic effects due to the iron content in the native platinum. Part III in the series will be in our July online issue.

Two Book Reviews
Volume 6: "Transition Metal Groups 9-12", from a 10-volume set of books: "Comprehensive Coordination Chemistry II: From Biology to Nanotechnology";, is reviewed by Ann K. Keep, Johnson Matthey Catalysts, Royston, U.K. Another book: "Electrodeposition of the Precious Metals: Osmium, Iridium, Rhodium, Rhenium, Ruthenium", by Terry Jones, is reviewed by Allin S. Pratt, Johnson Matthey Technology Centre.

Online Monitoring of Diesel Oil Degradation
Workers at Case Western Reserve University and Lubrizol Corp., U.S.A., have monitored diesel oil degradation using chronopotentiometric (CP) sensors. The sensors have an IrO₂ working electrode and can detect the total acid number and total base number of the oil. A sputter-formed CP sensor responsed well to oxidative degradation of the oil. However, sensor stability is a problem.

Final Analysis on Safeguarding Perfomance of Thermocouples
Roger Wilkinson, Johnson Matthey Noble Metals, Royston, U.K., describes RhPt thermocouples and some of the conditions that can affect their performance. Problems of contamination in service, Rh drift and looking after thermocouples will be discussed in the July online issue.

The April issue ends with a selection of abstracts based on recently published patent and scientific literature.

Platinum Metals Review is available on the internet from the publications section of the Platinum Today site or from the host site Ingenta Select.

Susan V. Ashton
Editor

Anyone with an active interest in the platinum group metals and their uses who does not have ready access to a copy of Platinum Metals Review and who may benefit from reading it, is invited to request a specimen copy from:

The Editor, Johnson Matthey PLC, Orchard Road, Royston, Hertfordshire SG8 5HE, United Kingdom; Fax +44 (0) 1763 256359; Email jmpmr@matthey.com