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

• Mo-doped Cu/SiO 2 catalysts were synthesized for DMO hydrogenation to ethanol. • The Mo 3 Cu 20 /SiO 2 sample exhibited the best ethanol yield (up to 94%). • The Lewis acidity and a balanced Cu 0 /Cu + resulted from the interaction between MoO x and Cu NPs play the pivotal role. • Excellent stability of Mo 3 Cu 20 /SiO 2 catalyst. 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/SiO 2 composite prepared by an ammonia evaporation hydrothermal method, and the Mo 3 Cu 20 /SiO 2 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 MoO x and Cu species, and the balanced Cu 0 /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 Mo 3 Cu 20 /SiO 2 is 79.9 kJ/mol, lower than that of Cu 20 /SiO 2 catalyst (108.1 kJ/mol).