Insights into the synergistic effect and catalytic mechanism in MnCeOx solid solution catalysts for low-temperature propane total oxidation

Abstract

A series of micro-mesoporous MnCeOx solid solution catalysts with various Mn/Ce molar ratios were successfully prepared using a facile chelating sol-gel method, and were studied for the total oxidation of propane. Mn1Ce1Ox exhibited the highest catalytic activity with a T90 = 255.5 ℃, which was 40 ℃ lower than that of pure Mn2O3. The superior performance was owing to the synergistic effect between Mn and Ce in Mn-Ce solid solution structure, which possesses a higher Mn4+/Mn ion ratio, stronger reducibility, and more active oxygen species. Meanwhile, the mechanism on total oxidation of propane over MnOx and MnCeOx was investigated by in-situ DRIFTs and density functional theory calculations. It revealed that Ce did not alter the reaction mechanism, but promoted the adsorption and activation of gaseous O2 on the catalyst surface. Overall, this study will provide more new insights into the catalytic mechanism of volatile organic compounds catalytic oxidation.