Total oxidation of propane over Pt-V/SiO2 catalysts: Remarkable enhancement of activity by vanadium promotion

The addition of V2O5 in the Pt/SiO2 catalysts greatly improves their activities for total oxidation of propane. The much higher activity on the catalyst with a Pt content of 2 wt.% and a V content of 10 wt.% (2 Pt-10 V/SiO2) (153.2 μmol gPt−1 s−1 at 200 °C) than that on the 2 Pt/SiO2 (9.8 μmol gPt−1 s−1) is due to the enhanced reducibility and surface acidity by the V2O5 promotion. Kinetic investigations reveal that the propane coverage on the 2 Pt-3 V/SiO2 is higher than that on the 2 Pt/SiO2, due to the presence of additional acid sites by V2O5 promotion. The rate determining step is the activation of propane on the partially oxygen covered Pt pair sites (*-O*), on which propane could be activated on the metallic Pt atom and react with oxygen on the oxidized Pt species. Additional Pt-V interfacial active sites may exist in the V-promoted catalyst, on which propane adsorbed on VOx could react with oxygen on the Pt oxide.