Selective Sieving Effect of Multi‐Atomic Bismuth Interfaces for Efficient Formate Electrosynthesis and Evolution at Industrial Current Density

Multi-atomic Bi interfaces (Bi⁰/Bi^δ+−O moiety) embedded in porous Bi₂O_3-x nanosheets featuring interfacial atomic sieving effect enabling efficient CO₂-to-formate conversion across pH ranges. The simultaneous production of formate on both the cathode and anode was also achieved by coupling CO₂ reduction reaction with the methanol oxidation reaction under industrial current density conditions. Further intermediacy of the concentrated formate for C–N coupling toward urea synthesis, establishing pathway for sustainable evolution.

Abstract

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.

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