Correlation between the physicochemical properties and catalytic performances of micro/mesoporous CoCeOx mixed oxides for propane combustion

Abstract A series of micro-mesoporous CoCeO x catalysts have been successfully prepared using a double template combining sol-gel method. The catalytic performance of novel CoCeO x catalysts are investigated and compared with pure Co 3 O 4 and CeO 2 catalysts for total oxidation of propane. It is found that the Co 1 Ce 1 catalyst shows the highest catalytic activity (T 50  = 217 °C) as well as a good reaction stability and water tolerance among the five catalysts. The Co 3 O 4 , CeO 2 and CoCeO x catalysts are characterized using XRD, BET, Raman, XPS, H 2 -TPR, O 2 -TPD, HRTEM, HAADF-STEM and in situ DRIFTS. The results demonstrate that the larger BET surface area, smaller grain size, stronger reducibility and more active oxygen species of the Co 1 Ce 1 catalyst are responsible for its outstanding catalytic performance among the five catalysts. Moreover, the synergistic effect between Co and Ce over CoCeO x catalysts are probably relevant to the formation of Co x Ce 1 −x O 2 −σ solid solution. In addition, on the basis of the results of XPS, kinetic analysis and in situ DRIFTS, the surface Co 3+ ions and active oxygen species are regarded as the major active sites of the CoCeO x catalysts for total oxidation of propane, and then a scheme of reaction model based on Langmuir-Hinshelwood mechanism is suggested at last. It can be expected that the micro-mesoporous CoCoO x catalysts are promising materials for VOCs removal, and the results in this research may also provide some new insights into the catalyst design and mechanism exploration for VOCs catalytic oxidation.