Morphology of platinum-alumina catalyst and elucidation of platinum ensemble

Abstract

Ensembling parameters have been evaluated for the vapour phase dehydrogenation of cyclohexane over platinum-alumina catalyst and platinum ensembles have been identified with the help of scanning electron microscopy (SEM) and statistical distribution studies. Platinum in the concentration range of 0.4-0.8% shows evidence for ensemble. The lowering of catalytic activity at high platinum loadings (> 1.4 Pt) is due to the diminution in the probability of existence of monoatomic ensemble and not to changes in the effective metal area accessible to the reactants.