Fabrication of silica supported Mn-Ce benzene oxidation catalyst by a simple and environment-friendly oxalate approach

A series of silica supported Mn-Ce composite oxides with different Mn/Ce molar ratios were obtained by a simple and environment-friendly oxalate route. The physical and chemical properties were characterized by TG, BET, SEM, TEM, XPS and TPR analysis. All catalysts showed excellent activity towards deep oxidation of benzene. The effects of Mn/Ce ratio, calcination temperature on the structure and catalytic activity of catalysts were investigated. Catalyst from nitrate precursor was also characterized to compare the influence of different precursors. The 6Mn4Ce sample from oxalate route sintered at 400 A degrees C showed the maximum reaction rate of 0.50 mmol gcat(-1)h(-1); T90 of the catalyst is 216 A degrees C. The catalytic activity is related to surface area, pore size distribution, surface elemental species, particle size distribution and low temperature reducibility which may derived from synergistic effect between manganese and cerium oxide. Compared with nitrate precursors, catalyst from oxalate route can be more finely dispersed on the pores of silica without damaging the pore structure of support. The role of silica is not only a support, but also an in situ reaction site for precursor's decomposition, which ensure the finely distribution of active components. In addition, the best catalyst showed good stability with prolonged time on stream