Skeletal Rearrangements of Hydrocarbons on Metals with Various Particles Sizes*

Abstract

The relative contributions of the various reaction mechanisms may be drastically changed by modifying the size of the metal particles. In the case of platinum catalysts for instance, two minimal particle sizes may be defined for the occurrence of selective cyclic and bond shift mechanisms respectively. The peculiar properties of the highly dispersed platinum catalysts with metal particles smaller than 10 Å may be explained either by the presence of pseudo-crystals with uncommon symmetry or, better, by electronic properties for the very small clusters that differ from the ones in the infinite crystal.