Enhancement of the electrochemical reduction of CO2 to methanol and suppression of H2 evolution over CuO nanowires

A highly efficient copper-catalyst (noble-metal free) was developed for the electrochemical reduction of CO2 (ERCO2) to methanol. Due to the nanowire structure of the catalyst, a remarkable ERCO2 selectivity was achieved, while the competing H2 evolution reaction (HER) was significantly suppressed for the overall range of potential tested. The developed copper-catalyst (CuO NWs) outperforms the single metal Cu-catalysts in aqueous environment. Under atmospheric conditions, methanol was produced at an overpotential of 410 mV with a faradaic efficiency (FE) of 66%, and 1.27 × 10−4 mol m−2 s−1 of production yield; which represents a 6.7% improvement over the previously reported value of 1.19 × 10−4 mol m−2 s−1. Interestingly, when the developed CuO NWs was used as a gas diffusion electrode (GDE) in a filter-press cell (more real industrial configuration), methanol remained as the major ERCO2 product with the same FE (66%).