Electrical anodization of Cu foil produces one-dimensional Cu nanowires of high surface areas, which turns to CuIn alloy nanowires by indium electrodeposition replacing edge site Cu atoms. An electrochemical pre-activation forms a highly conformal amorphous In(OH)(3) overlayer with oxygen vacancy on the CuIn alloy that facilitates CO2 adsorption to promote selective CO formation suppressing competing H-2 adsorption. Thus the activated CuIn alloy nanowires catalyse electrochemical CO2 conversion to CO with high CO selectivity (> 68.2%) and high current density (ca. -3.9 mAcm(-2)) at -0.6 Vim, which represents the higher partial CO current density (ca. -2.66 mAcm(-2)) than that of previously reported CuIn alloy powders without nanostructuring. The performance remains stable for more than 15 h without significant degradation.