Microwave-Assisted Facile Sol-Gel Synthesis of WO3-Based Silica Catalysts for Enhanced Activity in Glycerol Dehydration

WO3 is a promising catalyst for the production of acrolein from glycerol due to its high activity and selectivity. In this study, various metal oxides (W, Zr, and Nb) over colloidal silica (cSiO2) catalysts were obtained using a novel microwave-assisted synthesis method. The enhancement in the sol-gel grafting of metal oxides onto the cSiO2 support was achieved by microwave irradiation (MW) and compared to the conventional heating (CH). WO3-cSiO2 catalysts synthesized by microwave-assisted facile sol-gel synthesis were tested in the gas-phase glycerol dehydration reaction. The best catalytic performance (52.4% acrolein yield) was obtained over a 25%W-cSiO2 sample prepared by the MW method. The best yield results were obtained with a B/(B + L) ratio over 0.50 and with an optimum medium-strength acidity. The activity loss was correlated with the high-strength surface acidity.