Influence of preparation method on the properties of V-Sb-O catalysts for the ammoxidation of propane

The characteristics of V-Sb-O catalysts for the ammoxidn. of propane were studied. The prepn. method [solid state reaction, redox reaction in soln., sol-gel, copptn., heat treatment] has an important role on the final characteristics of the catalyst. Competition between the formation of the VSbO4 rutile-like phase and oxidn. of vanadium to form V5+-micro domains were obsd. During the catalytic reaction, the V5+-oxide undergoes redn. to form an inter-grown rutile-like V2O4 phase, but depending on the prepn. method, the V-oxide may not be accessible to the gaseous reactants. The Sb5+-oxide on the surface of vanadium-antimonate is active in the synthesis of acrylonitrile. Vanadium catalyzes the reoxidn. of antimony, and plays other roles in the mechanism of oxidative dehydrogenation of propane to propylene and in the side reaction of ammonia oxidn. to N2. [on SciFinder(R)]