Platinum Metals Review - Volume 18, Issue 2, 1974

Platinum can be strengthened very effectively for high temperature use by the addition of small quantities of a highly dispersed non-metallic phase, and recent work in the Johnson Matthey Research Laboratories has established processes which allow such a composite material to be produced consistently and reliably on an industrial scale. The new material, known commercially as ZGS platinum, is significantly stronger and more creep resistant than the conventional high temperature rhodium-platinum alloys, and yet retains the traditional characteristics which have given platinum its unique role in many industrial applications. This article describes the physical and mechanical properties of this dispersion strengthened product, highlights some of the areas in which it has been employed to advantage and discusses design factors in such uses.

Reliable kinetic rate data have not previously been available for the oxidation of carbon monoxide on platinum catalysts used in the control of automobile exhaust emissions. This paper discusses results of studies using an isothermal differential catalyst bed and confirms that mass transfer and pore diffusion did not control the reaction rate, so that the observed kinetics represent the true surface reaction rates.

Almost all industrial catalysts are heterogeneous, the reaction taking place on a solid surface. During the past decade homogeneous catalysts, soluble in the liquid phase reactant, have received a great deal of attention, although they have so far found only limited industrial use, chiefly because of the difficulty of their separation from the reaction products. More recently an intermediate type, made by attaching the active metal complex to an insoluble polymer support, has been found to offer a promising new range of catalysts for the future. It is likely that a large proportion of these will be based on the platinum group metals.