High‐Performance Bi‐Based Catalysts for CO₂ Reduction: In Situ Formation of Bi/Bi₂O₂CO₃ and Enhanced Formate Production

Abstract The unavoidable self‐reduction of Bismuth (Bi)‐based catalysts to zero‐valence Bi often results in detrimental adsorption of OCHO * , leading to unsatisfactory selectivity of HCOOH in the electroreduction of carbon dioxide (CO 2 ). A novel Bi‐tannin (Bi‐TA) complex is developed, which undergoes in situ reconstruction into a Bi/Bi₂O₂CO₃ phase during CO 2 reduction. This reconstructed catalyst exhibits high activity and selectivity, achieving a Faradaic Efficiency (FE) for formate production exceeding 90%, peaking at 96%. Operando spectroscopic and theoretical analyses reveal that the Bi δ+ active site in Bi/Bi₂O₂CO₃ significantly enhances the formation of the OCHO * intermediate, crucial for formate production. The study offers a promising approach to overcoming the limitations of Bi‐based catalysts in CO 2 reduction to formate.