Copper-based electrocatalysts have shown great potential for electrolytic CO2 reduction (CO2RR) to value-added multi-carbon products but suffer from poor selectivity and activity due to the uncontrollable CO adsorption and sluggish C-C coupling kinetics. Herein, we develop a dopant-driven interfacial engineering strategy by incorporating chromium (Cr) into copper oxide, which in situ reconstructs to Cu-CrOx heterointerfaces under CO2RR conditions. Combined experimental and theoretical analyses reveal that Lewis acidic CrOx clusters tailor the electronic structure of Cu sites, thereby strengthening the CO adsorption and accelerating C-C coupling. The Cu-CrOx interface also promotes water dissociation to supply active hydrogen species for multiple hydrogenation steps. The optimized catalyst achieves a 59.2% faradaic efficiency for ethylene and maintains stable operation for over 110 h at 2.45 V in a membrane electrode assembly electrolyzer. This work highlights dopant-enabled interfacial engineering as a versatile strategy for steering CO2RR activity and selectivity toward multi-carbon products, offering mechanistic insights that advance the field.
Wei et al. (2026) studied this question.