Recent advances in single crystal and facet dependency of copper electrodes on electrochemical CO2 reduction

Investigations on electrochemical CO₂ reduction reaction (eCO2RR) on copper (Cu) provide instructive information for the understanding and development of Cu-based catalysts and thus help improve their eCO2RR selectivity toward desired products. Although most studies on the reaction mechanism rely on computational simulations, experiments conducted on well-defined single-crystal structures are able to effectively mirror the ideal surfaces employed in simulation studies and thus convey insightful knowledge on the structure–performance correlation of Cu catalysts in eCO2RR. This mini-review provides an overview on state-of-the-art development of Cu single crystals and their facet dependency in eCO2RR in the recent years, followed by an outlook and perspective on what can be expected in the future.