Selective electrochemical reduction of CO₂ to CO on CuO-derived Cu nanowires

In this work, we report a new synthesis method to prepare a Cu nanowire electrocatalyst for selective CO₂ reduction at room temperature and atmospheric pressure. Cu nanowire array electrodes were prepared through a two-step synthesis of Cu(OH)₂ and CuO nanowire arrays on Cu foil substrates and a subsequent electrochemical reduction of the CuO nanowire arrays. The Cu nanowire arrays are able to electrochemically reduce CO₂ to CO with a faradaic efficiency of ∼50% at a moderate overpotential of 490 mV, which is significantly higher than that of polycrystalline Cu foil catalysts at identical conditions. The improved faradaic efficiency for the reduction of CO₂ to CO is ascribed to the enhanced stabilization for the CO₂^- intermediate on the high surface area Cu nanowire arrays.