Pt-Mo bimetallic catalysts supported on y-zeolite: Part III. Specific role of molybdenum in hydrocarbon adsorption and conversion

Abstract Pt-Mo bimetallic catalysts prepared by adsorption and decomposition of Mo(CO) 6 on 1 nm Pt aggregates supported on Y-zeolite exhibit enhanced hydrogenolysis activity in n-butane conversion. This is due to the participation of Mo atoms in the reaction mechanism. The TPD of adsorbed ethane and TP surface reaction of D 2 with the hydrocarbon fragments show that the saturated hydrocarbons are strongly dissociated on the Mo atoms, which accounts for the hydrogenolysis enhancement. On the other hand, benzene hydrogenation proceeds only on the fraction of platinum not covered by Mo atoms; the catalytic activity and the H 2 chemisorption decrease simultaneously. Pt-Mo-Y catalysts exhibit a higher resistance to sulfur poisoning, but the poisoning is irreversible.