Selective Sieving Effect of Multi-Atomic Bismuth Interfaces for Efficient Formate Electrosynthesis and Evolution at...

Constructing multi-atomic interfaces architectures is promising for electrocatalytic CO₂ conversion, yet their synthesis and stability under industrial current densities remain challenging. Herein, multi-atomic Bi interfaces (Bi⁰/Bi^δ+-O moiety) were precisely engineered by embedding atomically dispersed Bi centers, encompassing Bi single atoms and Bi atomic clusters into the substrate of porous Bi₂O_3-x nanosheets. The composite showcases outstanding CO₂ conversion performance across a wide pH range, attaining remarkable Faradaic efficiency for formate (FE_formate) of 96.48% (at ultralow potential of -0.5 V versus RHE) and 92.26% in alkaline and neutral electrolytes, along with exceptional long-term stability over 150 h. Depending on the designed CH₃OH electrooxidation catalyst (CuO_x/ZnCo(OH)_x) at the anode to couple with CO₂ conversion, symmetrical/asymmetrical electrolyzers were developed. The approach could obtain high-added value products with FE_formate >90% at both electrodes, achieving a production rate of 4980 µmol h^-1 cm^-2 under industrial current density. Combined in situ characterizations and theoretical calculations unravel that multiple atomic interfaces featuring interfacial atomic sieving effects effectively enhance preferential binding of *H and *CO₂ to form *OCHO, while simultaneously suppressing the undesired recombination of hydrogen species into H₂, rationalizing the high selectivity. Further intermediacy of concentrated formate precursors for subsequent C-N coupling toward urea synthesis, establishing a pathway for sustainable evolution.