Oxidative dehydrogenation of propane over niobia supported vanadium oxide catalysts

Abstract

Oxidative dehydrogenation (ODH) of propane is examined over a series of catalysts, which include Nb 2O 5 supported monolayer V 2O 5 catalysts, bulk vanadia-niobia with different vanadium oxide loadings and prepared by four different methods, V 2O 5and Nb 2O 5. The intrinsic activity (TOF) of the samples studied indicates that vanadium containing active sites are indispensable for catalytic oxidative dehydrogenation of propane. Variations in the chemical environment of the vanadium ion do not cause significant changes in activity per site and, hence, all samples show similar TOF when the rates are normalised to the concentration of V on the surface. Selectivity to propene on the other hand strongly depends on the nature of the catalyst because readsorption and interaction of propene with the acid sites leads to total oxidation. Optimization of the weak sorption of propene is, therefore, concluded to be the key factor for the design of selective oxidative dehydrogenation catalysts.