Catalysis Letters, Vol.126, No.1-2, 155-163, 2008
Preparation of Mesoporous V-Ce-Ti-O for the Selective Oxidation of Methanol to Dimethoxymethane
Mesoporous V-Ce-Ti-O oxides were synthesized through the combination of sol-gel and hydrothermal methods and were characterized by different techniques. N-2 adsorption showed that the mesoporous oxides with 0-20 wt.% V2O5 possessed the surface areas of about 160 m(2) g(-1) with narrow pore size distribution centered around 4-5 nm. Vanadium species were highly dispersed in the samples, as confirmed by the wide angle XRD and Raman spectroscopy. The surface acidity of the materials was determined by the microcalorimetric adsorption of NH3. Temperature programmed reduction and O-2 chemisorption were used to probe the redox property of the materials. It was found that the mesoporous V-Ce-Ti-O possessed bifunctional characters of acidic and redox properties that catalyzed the oxidation of methanol to dimethoxymethane (DMM). These bifunctional characters were further enhanced by the addition of V2O5 and SO42- onto V-Ce-Ti-O simultaneously. Such supported catalysts exhibited excellent performance for the selective oxidation of methanol to DMM. Specifically, 72% conversion of methanol with 85% selectivity to DMM was achieved at 423 K over a SO42--V2O5/V-Ce-Ti-O catalyst.
Keywords:Mesoporous V-Ce-Ti-O;Surface acidity;Surface redox property;Oxidation of methanol;Synthesis of dimethoxymethane