One Step Template-Free Synthesis of Mesoporous MnOx/CeO2 Nanocomposite Oxides with Enhanced Low Temperature Catalytic Activity for CO and Hydrocarbon Oxidation

Abstract

A green environment-friendly preparation method with template-free facile redox precipitation strategy was proposed to synthesize a series of mesoporous MnOx/CeO2 nano-composite oxides and were applied to catalytic oxidation diesel engine exhaust of CO and CH. The catalysts were characterized by XRD, N2 adsorption–desorption, TEM/SEM, XPS, H2-TPR and O2-TPO. Among these catalysts, the optimized sample MnOx/CeO2-64 achieved high catalytic activity (CO: T100 = 150 °C; C3H6: T100 = 190 °C; C3H8: T100 = 230 °C) and good durability. The superior catalytic activity of the catalyst could be ascribed to the generation of a large number of active oxygen species due to a synergetic catalytic effect between Ce/Mn with multiple oxidation states. The results of H2-TPR and O2-TPO indicated that stronger redox capacity contributed to the excellent catalytic oxidation performance. In addition, a possible reaction pathway was proposed for clarification this catalytic process. We propose a facile template-free strategy to prepare mesoporous nano-composites by one step redox precipitation method using H2O2 as reductant-oxidant, which shows the advantages of mild condition, simple process and environmental protection.