Insight into catalytic properties of Co3O4-CeO2 binary oxides for propane total oxidation

A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co) molar ratios were synthesized using a citric acid method, and their catalytic properties toward the total oxidation of propane were examined. The activities of the catalysts decrease in the order CoCeOx-70 > CoCeOx-90 > Co3O4 > CoCeOx-50 > CoCeOx-20 > CeO2. CoCeOx-70 (Co/(Ce+Co) = 70% molar ratio) exhibits the highest catalytic activity toward the total oxidation of propane, of which the T90 is 310 °C (GHSV = 120000 mL h−1 g−1), which is 25 °C lower than that of pure Co3O4. The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4, the improvement of the low-temperature reducibility, and the increase in the number of active oxygen species. In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism, but promotes the adsorption and activation of propane on the catalyst surface. The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion, and the catalyst is more sensitive to water vapor than to CO2. In addition, CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.