Ordered crystalline mesoporous oxides as catalysts for CO oxidation

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, Mn₂O ₃, 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 (T₅₀ = 39 °C).