A series of vanadium-loaded ceria catalysts was prepared and their activity and selectivity towards propane oxidative dehydrogenation (ODH) was studied. The V-loaded samples all showed similar behavior, with high selectivity at low conversion (< 5%) dropping off exponentially with increasing conversion (and the inherent higher temperatures). The 6VCe sample showed the highest selectivity to proylpene at ∼ 33% and selectivity decreased with increasing V content. The ceria support itself showed virtually no selectivity towards propylene (maximum ∼ 2%) instead converting propane directly to CO2 almost exclusively. For any given temperature, the 6VCe sample showed the highest yield, and the unpromoted support the lowest. In the 6 wt % V2O5 catalyst, hydrated surface VOx species were present although they underwent conversion to CeVo4 at above 573 K. The low reducibility of these surface vanadates was linked to the oxidation activity. Surface polyvanadates species were responsible for the selective ODH of propane with V-O-V and V-O-Ce being the active oxygen species.
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