Hydrogenation of dimethyl oxalate to ethanol over Mo-doped Cu/SiO2 catalyst

Abstract

The environmentally-benign hydrogenation of dimethyl oxalate to produce ethanol has attracted considerable attention recently, and the yield of which remains a challenge for the commonly used Cu-based catalysts. Herein we reported a molybdenum-doped Cu catalyst synthesized by impregnating Mo on the Cu/SiO2 composite prepared by an ammonia evaporation hydrothermal method, and the Mo3Cu20/SiO2 sample exhibited the best compromise between activity and ethanol selectivity, acting as a robust catalyst (460 h time on stream) with a high ethanol yield (∼94 %). It is demonstrated that Mo doping elevates the amount of surface Cu+ species through the strong interaction between MoOx and Cu species, and the balanced Cu0/Cu+ ratio and enhanced surface acidity resulted by Mo addition afford the high ethanol selectivity through facilitating the dehydroxylation of ethylene glycol, whose activation energy over Mo3Cu20/SiO2 is 79.9 kJ/mol, lower than that of Cu20/SiO2 catalyst (108.1 kJ/mol).