Engineering Atom‐Scale Cascade Catalysis via Multi‐Active Site Collaboration for Ampere‐Level CO₂ Electroreduction to C₂₊ Products

Abstract Electrochemical reduction of CO₂ to value‐added multicarbon (C₂₊) productions offers an attractive route for renewable energy storage and CO₂ utilization, but it remains challenging to achieve high C₂₊ selectivity at industrial‐level current density. Herein, a Mo₁Cu single‐atom alloy (SAA) catalyst is reported that displays a remarkable C₂₊ Faradaic efficiency of 86.4% under 0.80 A cm⁻². Furthermore, the C₂₊ partial current density over Mo₁Cu reaches 1.33 A cm⁻² with a Faradaic efficiency surpasses 74.3%. The combination of operando spectroscopy and density functional theory (DFT) indicates the as‐prepared Mo₁Cu SAA catalyst enables atom‐scale cascade catalysis via multi‐active site collaboration. The introduced Mo sites promote the H₂O dissociation to fabricate active ^*H, meanwhile, the Cu sites (Cu⁰) far from Mo atom are active sites for the CO₂ activation toward CO. Further, CO and ^*H are captured by the adjacent Cu sites (Cu^&+) near Mo atom, accelerating CO conversion and C─C coupling process. Our findings benefit the design of tandem electrocatalysts at atomic scale for transforming CO₂ to multicarbon products under a high conversion rate.