A highly efficient nickel doped Cu/SiO2 catalyst was investigated for the vapor-phase selective hydrogenation of dimethyl oxalate to ethanol. Nickel species were introduced into a silica-supported copper catalyst by an impregnation method. An appropriate amount of Ni significantly enhanced the ability of H-2 to adsorb and dissociate on the Cu/SiO2 catalyst. Consequently, the catalytic performance of the catalyst was greatly improved and a selectivity for ethanol of 90% was achieved with the catalyst with 1 wt% Ni. Moreover, the addition of nickel resulted in the formation of Cu-Ni bimetallic nanoparticles and surface segregation occurs in bimetallic nanoparticles. When excessive amount of nickel was introduced into the Cu/SiO2 catalyst, the catalytic performance deteriorated because of serious surface segregation and aggregation of the copper. (C) 2016 Elsevier B.V. All rights reserved.