Novel Rh/TiO2 and Ir/TiO2 Catalysts for n-Butane Isomerization and Dehydrogenation

Article abstract of DOI:10.1021/j150664a021

An ion-exchange preparation of TiO2-supported Rh and Ir which produces a 100percent dispersed, low metal loading (0.3percent) catalyst is described.When these catalysts are reduced at high temperature (773 K), they exhibit a unique activity for alkane isomerization and dehydrogenation.Hydrogenolysis, greatly suppressed on these catalysts, has an unusual positive order in hydrogen and a relatively high selectivity for terminal vs. central C-C bond breaking of n-butane compared to impreganated Rh and Ir catalysts.It is proposed that this behavior is the result of the strong metal-support interaction which results in a great depression and a change in the mechanism of hydrogenolysis, the mechanism being one where alkane isomerization competes with hydrogenolysis.Alkane dehydrogenation takes place on sites different from those where isomerization occurs.These sites may not involve zerovalent metal.