Vanadium and niobium mixed-oxide catalysts obtained via sol-gel: preparation and catalytic behaviour in oxidative dehydrogenation of propane

mong the various catalysts proposed for the oxidative dehydrogenation (ODH) of propane, mixed oxide catalysts containing vanadium are the most frequently studied. A study on the optimization of the hydrolytic sol-gel preparation method to achieve the highest possible control of the molecular scale interdispersion of the mixed-oxide phases was carried out. A Nb-V synergistic effect in the ODH of propane characterized the 4.5:1 Nb/V sample, which showed both higher activity and selectivity to propylene than the 1:1 Nb/V samples. The 9:1 Nb/V sample containing the lowest amount of V behaved similarly to pure Nb2O5, showing rather poor activity and high selectivity to propylene, about 50%. Both activity and selectivity increased only slightly with the 1:1 Nb/V (citric acid) system, containing V mainly as Nb-V mixed oxide. The presence of small amount of V-O-V bonds as crystalline V2O5 increased significantly the catalyst activity of precipitated 1:1 Nb/V samples. This is an abstract of a paper presented at the International Workshop on Oxide Based Materials: New sources, novel phases, new applications.