High Selectivity Towards Formate Production by Electrochemical Reduction of Carbon Dioxide at Copper–Bismuth Dendrites

Abstract The electrochemical reduction of CO 2 provides an alternative carbon‐neutral path for renewable synthesis of fuels and value‐added chemicals. This work demonstrates that dendritic, bimetallic Cu–Bi electrocatalysts with nanometer‐sized grains are capable of formate generation with a high selectivity. Optimizing composition of electrocatalyst could achieve a faradic efficiency of 90 % at −0.8 to −0.9 V RHE , and a partial current of more than 2 mA cm −2 . The combination of Cu with Bi enables modulation of the adsorption strength of intermediates. This leads to an increased selectivity and suppressed formation of spurious species, especially hydrogen and CO. Comparison of product distribution for Cu–In versus Cu–Bi indicated that Bi is essential to induce a favorable adsorption configuration of the intermediate species and to promote formate production.