Propane Oxidative Dehydrogenation on V–Sb/ZrO2 Catalysts

The catalytic properties of V–Sb/ZrO 2 and bulk Sb/V catalysts for the oxidative dehydrogenation of propane were studied. Samples were characterized by nitrogen adsorption, temperature-programmed reduction, temperature-programmed pyridine desorption and photoelectron spectroscopic techniques. Vanadia promotes the transition of tetragonal to monoclinic zirconia and the formation of ZrV 2 O 7 . Surface V and Sb oxide species do not appear to interact among them below monolayer coverage, but SbVO4 forms above monolayer. Simultaneously the excess of antimony forms α-Sb 2 O 4 . Activity and selectivity show no dependence on the acidity of the catalysts. However, there is a strong dependence of activity/selectivity on composition; surface vanadium species are active for propane oxidative dehydrogenation and the presence of Sb, affording rutile VSbO 4 phase makes the system selective to C 3 H 6 , this is believed to be related to the redox cycle involving dispersed V 5+ species and lattice reduced vanadium site in the rutile VSbO 4 phase.