Ordered Crystalline Mesoporous Oxides as Catalysts for CO Oxidation

Abstract

Crystalline mesoporous metal oxides have attracted considerable attention recently, but their catalytic applications have rarely been studied. In this work, a series of crystalline three-dimensional mesoporous metal oxides (i.e., CeO2, Co3O4, Cr2O3, CuO, Fe2O3, β-MnO2, Mn2O3, Mn3O4, NiO, and NiCoMnO4) were prepared using the mesoporous silica KIT-6 as a hard template. These ordered mesoporous metal oxides with highly crystalline walls were characterized by PXRD, TEM, N2 adsorption and evaluated as CO oxidation catalysts. These mesoporous materials, except for mesoporous Fe2O3, exhibit much higher catalytic activities than their bulk counterparts. In particular, mesoporous Co3O4, β-MnO2, and NiO show appreciable CO oxidation activity below 0 °C, and the catalytic activities of mesoporous β-MnO2, and NiO are even higher than those of their nanoparticulate counterparts with large surface areas. β-MnO2 is particularly interesting because it combines low cost and low toxicity with high activity (T 50 = 39 °C).