Influence of Metal Loading, Oxidation State and Ionomer Chemistry on the Performance of Carbon‐Supported Copper Electrocatalysts for the Reduction of Carbon Dioxide

The electrochemical conversion of carbon dioxide (CO2RR) to value‐added chemicals is a promising approach toward the defossilization of the chemical and energy industries. Copper‐based electrocatalysts have been favored to perform CO 2 reduction, due to their unique selectivity toward valuable products compared to other metals. However, optimizing Cu content in efficient cathodes remains a challenge, as current high‐performance architectures typically require high copper loadings to operate. In this study, we investigate the properties of carbon‐supported copper‐based electrocatalysts for the CO2RR in a membrane‐electrode assembly configuration. In addition to varying the metal loading, we investigate the influence of the oxidation state of copper and the chemical composition of the electrocatalytic layer and electrolyte on the performance. We find that supported Cu/C and CuO/C electrocatalysts can operate with a high activity toward CO2RR (with current densities in the order of 100 mA.cm −2 ). We then propose an optimization of our CuO/C electrocatalyst, reaching more than 50 mA.cm −2 for ethylene production for a cell voltage of 3 V and a Cu loading of 30 wt%. This represents a significant improvement in performance for a lower metal loading compared to state‐of‐the‐art commercial Cu/C electrocatalysts tested under the same conditions.