Platinum Metals Review - Volume 27, Issue 4, 1983

Since the introduction in 1974 of catalytic converters for automotive emission control in the United States significant advances have been made in the design of durable monolith supported catalysts for the control of carbon monoxide, unburnt hydrocarbon and nitrogen oxide emissions. However, high temperature durability, has been a significant problem, particularly of three-way catalysts. Johnson Matthey Inc. have examined the fundamental nature of catalyst deactivation under high temperature conditions. This has been found to be associated with problems as diverse as adhesion of the catalyst layer to the ceramic monolith, interaction of the platinum metals with the underlying support and poor thermal stability of base metal promoters incorporated in the catalyst. As a result a new generation of catalysts has now been developed with substantially improved thermal stability.

The purification or separation of hydrogen has traditionally been based on solid-state diffusion technology utilising noble metal membranes. The development of this technology, which has been centred around improved diffusion membrane materials based on the silver-palladium alloy system, is reviewed in this paper. It is shown that, despite the emergence of alternative techniques, diffusion technology based on silver-palladium membranes remains the most suitable technique for the production of high purity hydrogen, a product which is required increasingly in many high technology applications.

What does the ground state of conduction electrons of metals look like, if the temperature is lowered further and further? This question has been fascinating low temperature physicists for a long time. Nowadays we know that most metallic elements become superconducting at sufficiently low temperatures. In 1964 the superconductivity of tungsten was discovered by lowering the temperature to 15 mK above absolute zero. After a long pause due to the limits of refrigeration, a new superconducting element has now been discovered: rhodium. Various samples fabricated with rhodium sponge were installed in a special set-up in the world’s most powerful refrigerator at the Kernforschungsanlage Jülich. Temperatures down to 50 μK were used to investigate the superconductive properties of rhodium, which shows a superconductive transition at 325 μK.

In 1824, the British government sought to keep pace with continental advances in optical glass manufacture by funding research into the area. Faraday was put in charge of the experimental investigation and he relied heavily on platinum for vessels and instruments. Throughout the researches he was aided by William Hyde Wollaston, who manufactured and supplied the platinum initially used.