Surfactant-Assisted Synthesis, Characterizations, and Catalytic Oxidation Mechanisms of the Mesoporous MnOx−CeO2 and Pd/MnOx−CeO2 Catalysts Used for CO and C3H8 Oxidation

Abstract

A series of mesoporous MnOx−CeO2 binary oxide catalysts with high specific surface areas were prepared by surfactant-assisted precipitation. The CO and C3H8 oxidation reactions were used as model reactions to evaluate their catalytic performance. The techniques of N2 adsorption/desorption, XRD, XPS, TPR, TPO, TPD, and in situ DRIFTS were employed for catalyst characterization. It is found that the activity for CO and C3H8 oxidation of the catalysts exhibits a volcano-type behavior with the increase of Mn content. The catalyst with a Mn/Ce ratio of 4/6, possessing a high specific surface area of 215 m2/g, exhibits the best catalytic activity, which is related not only to its highest reducibility and oxygen-activation ability, as revealed by TPR and TPO, but also to the formation of more active oxygen species on the MnOx−CeO2 interface as identified by TPD. After the addition of a small amount of Pd to the MnOx−CeO2 catalyst, its activity for CO oxidation is greatly enhanced, due to the acceleration of gas-...