Electrocatalytically converting CO2 to hydrocarbons is a very attractive way to use the excess electricity generated from renewable energies. In this paper, we report the electrochemical reduction of CO2 based on Cu nanowire arrays. The Cu nanostructured electrode shows much higher current density than polycrystalline Cu. By sputter coating a thin layer of Au on the Cu nanowires, the Faradaic efficiency (FE) of CO can exceed 30%. At an overpotential of 540 mV with respect to the formation of CO, the Cu/Au core-shell nanowire array electrode catalyses the formation of syngas, a very useful gas mixture, with a stable CO/H-2 ratio. (C) 2017 Elsevier Ltd. All rights reserved.