In-Situ Constructuring of Copper-Doped Bismuth Catalyst for Highly Efficient CO2 Electrolysis to Formate in Ampere-Level

CO2 electrochemical reduction (CO2RR) can mitigate environmental issues while providing valuable products, yet challenging in activity, selectivity, and stability. Here, a CuS-Bi2S3 heterojunction precursor is reported that can in situ reconstruct to Cu-doped Bismuth (CDB) electrocatalyst during CO2RR. The CDB exhibits an industrial-compatible current density of -1.1 A cm(-2) and a record-high formate formation rate of 21.0 mmol h(-1) cm(-2) at -0.86 V versus the reversible hydrogen electrode toward CO2RR to formate, dramatically outperforming currently reported catalysts. Importantly, the ultrawide potential region of 1050 mV with high formate Faradaic efficiency of over 90% and superior long-term stability for more than 100 h at -400 mA cm(-2) can also be realized. Experimental and theoretical studies reveal that the remarkable CO2RR performance of CDB results from the doping effect of Cu which optimizes adsorption of the *OCHO and boosts the structural stability of metallic bismuth catalyst. This study provides valuable inspiration for the design of element-doping electrocatalysts to enhance catalytic activity and durability.