Propane dehydrogenation was studied over alumina-supported catalysts at 500°C and 600°C. The dilution of catalytically active platinum (Pt) atoms with catalytically inactive tin (Sn) atoms was employed as a means of studying the activity of ensemble of contiguous Pt atoms. For dilution of Pt catalyst with Sn, the catalyst has a higher activity and selectivity due to Sn, which reduces the Pt ensembles that are required for side reactions. It is found that high reaction temperature (600°C) gives higher conversion and selectivity. Moreover, the addition of both Sn and Li to the Pt/AlO promotes the activity of dehydrogenation reaction and decrease the rate of coke formation on the catalyst surface. The catalytic effects of two promoters (Sn and Li) exhibit a surprising univormity; give the higher conversion and selectivity of dehydrogenation reaction than one promoter.
