Surface Engineering on Commercial Cu Foil for Steering C₂H₄/CH₄ Ratio in CO₂ Electroreduction

Designing catalysts with high selectivity toward C₂ products in CO₂ electroreduction is crucial to energy storage and sustainable development. Here, we propose a Cu foil kinetic model with abundant nanocavities possessing higher reaction rate constant k to steer the ratio of C₂H₄ to the competing CH₄ during CO₂ electroreduction. Chemical kinetic simulation demonstrates that the nanocavities could enrich the adsorbed CO surface concentration (θ_COad), while the higher k helps to lower the C-C coupling barrier for CO intermediates, thus favoring the formation of C₂H₄. The commercial Cu foil treated with cyclic voltammetry is used to match this model, displaying a remarkable C₂H₄/CH₄ ratio of 4.11, which is 18 times larger than that on the pristine Cu foil. This work offers a handy strategy for surface modification and provides new insights into the C-C coupling and the C₂H₄ selectivity in terms of mass transfer flux and energy barrier.