Copper–Silver Bimetallic Nanowire Arrays for Electrochemical Reduction of Carbon Dioxide

The electrochemical conversion of carbon dioxide (CO₂) into gaseous or liquid fuels has the potential to store renewable energies and reduce carbon emissions. Here, we report a three-step synthesis using Cu⁻Ag bimetallic nanowire arrays as catalysts for electrochemical reduction of CO₂. CuO/Cu₂O nanowires were first grown by thermal oxidation of copper mesh in ambient air and then reduced by annealing in the presence of hydrogen to form Cu nanowires. Cu⁻Ag bimetallic nanowires were then produced via galvanic replacement between Cu nanowires and the Ag⁺ precursor. The Cu⁻Ag nanowires showed enhanced catalytic performance over Cu nanowires for electrochemical reduction of CO₂, which could be ascribed to the incorporation of Ag into Cu nanowires leading to suppression of hydrogen evolution. Our work provides a method for tuning the selectivity of copper nanocatalysts for CO₂ reduction by controlling their composition.