Simple synthesis of mesoporous TiO2 and its application for methanol selective oxidation to dimethoxymethane

Mesoporous TiO2 was prepared by hydrolysis of Ti(OBu)4 without template. The material was further used to support VOx species as effective catalyst for methanol selective oxidation-condensation to dimethoxymethane (DMM). XRD patterns of both the as prepared TiO2 material and the VOx/TiO2 catalyst show pure anatase phase, but no V2O5 diffraction peaks even for 20% V2O5 loading was detected in the final catalyst. N2 adsorption-desorption isotherms of both samples displayed type Ⅳ isotherms with H2-like hysteresis loop,indicating the presence of mesoporous structure. The BET surface areas of the mesoporous TiO2 and the VOx/TiO2 catalyst are 290m2/g and 126m2/g, respectively, and the pore size are 2-4nm and 4-15nm. When used for methanol oxidation-condensation, the VOx/TiO2 catalyst showed 55% conversion of methanol and 85% selectivity of dimethoxymethane (DMM). This high yield of DMM (47%) could be attributed to a combined effect of the high surface area of meso-structured TiO2 which leads to a high dispersion of VOx species and the modification with Ti(SO4)2 for generating suitable acidic sites.