Roughness Effect of Cu on Electrocatalytic CO 2 Reduction towards C 2 H 4

Electrochemical reduction of CO2 to produce valuable multi-carbon products is a promising avenue for promoting CO2 conversion and achieving renewable energy storage, and it has also attracted considerable attention recently. However, the synthesis of Cu electrode with a controllable electrochemical active surface area (ECSA) to understand its role in CO2 reduction to C2 H4 remains challenging. Herein, a series of Cu electrodes with different ECSA is synthesized through a simple oxidation-reduction approach. We reveal that the improved selectivity of C2 H4 is proportional to the ECSA of Cu in the low ECSA range, and a further increase in ECSA has a negligible effect on its selectivity. The enlarged surface area could strengthen the local pH effect near the surface of Cu electrode and suppress the generation of C1 products as well as H2 . The study provides a feasible strategy to rationally design electrocatalysts with high electrochemical CO2 reduction performances.