Asymmetric, Corner-Sharing CuO and CuO Motifs in Cu-Based Metallic Perovskite Oxides Boosting Asymmetric C─C Coupling for CO Electroreduction to C.

Cu-based perovskite oxides feature significant potential for CO electroreduction (CORR) but encounter insufficient C selectivity primarily due to the inherent symmetric charge distribution at Cu sites hindering asymmetric C─C coupling. Here we report a unique type of Cu-based metallic perovskite oxides with asymmetric, corner-sharing CuO and CuO motifs to boost asymmetric C─C coupling for efficient CO-to-C conversion. For the proof-of-concept catalyst of LaBaCuO, their ordered, corner-sharing CuO pyramids and CuO octahedra feature localized charge density redistribution, creating abundant asymmetric Cu─Cu dual sites with distinct electronic structures and also strengthening Cu─O covalency. In CORR (in both alkaline and acidic media), LaBaCuO greatly promotes C formation while producing negligible CH, showing a Faradaic efficiency ratio (C to CH) of up to 180. Moreover, LaBaCuO, achieving a remarkable C Faradaic efficiency of 85.0% at 400 mA cm, together with well-boosted stability, outperforms previously reported Cu-based-perovskite catalysts. Our experiments and theoretical calculations attribute the superb performance mainly to the following factors: the asymmetric CuO─CuO sites promoting differentiated *CO adsorption/hydrogenation to favor asymmetric *CO─*CHO coupling; the strengthened Cu─O covalency stabilizing the Cu sites. Extending this strategy to two additional pairs of Cu-based perovskite oxides generates similarly successful results.