SUPPORTED PLATINUM, PALLADIUM, AND RHODIUM CATALYSTS

This paper surveys the results of an investigation of the hydrogenolysis of methylcyclopentane, the hydrogenation of propylene, and isotopic exchange between deuterium and 2,2-dimethylbutane and cyclopentane on Pt/SiO//2, Pt/Al//2O//3, Pd/SiO//2, and Rh/SiO//2 catalysts. It also summarizes the results of the characterization of the catalysts by X-ray line profile analysis and EXAFS, by chemisorption techniques, and by study of the removal from the oxide from the metal particles of the catalysts by hydrogen. Pretreatment conditions are as important as particle size in determining the catalytic properties of these materials. The effects of differing conditions of pretreatment probably result largely from influence upon surface morphology, but exposure to hydrogen and cooling in hydrogen from higher temperatures seem to result in special effects. The metal particles do not appear in general to be bound by smooth (111) and (100) planes.