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.
|Titolo:||Vanadium and niobium mixed-oxide catalysts obtained via sol-gel: preparation and catalytic behaviour in oxidative dehydrogenation of propane|
|Data di pubblicazione:||2005|
|Appare nelle tipologie:||Relazione (in Volume)|