Propane oxidative dehydrogenation on V-Sb/ZrO2 catalysts

Abstract

The catalytic properties of V?Sb/ZrO2 and bulk Sb/V catalysts for the oxidative dehydrogenation of propane were studied. Samples were characterized by nitrogenadsorption, temperature-programmed reduction, temperature-programmed pyridine desorption and photoelectron spectroscopic techniques. Vanadia promotes the transition of tetragonal to monoclinic zirconia and the formation of ZrV2O7. Surface V and Sb oxide species do not appear to interact among them below monolayer coverage, but SbVO4 forms above monolayer. Simultaneously the excessof antimony forms a-Sb2O4. 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 VSbO4 phase makes the system selective to C3H6, this is believed to be related to the redox cycle involving dispersed V5+ species and lattice reduced vanadium site in the rutile VSbO4 phase.