LAUSR

Electrochemical reduction of CO2 to high‐value chemical feedstocks, such as formate, is one of the most promising ways to alleviate the greenhouse effect. Unfortunately, the exploration of electrocatalysts with high activity and selectivity over a wide potential window (especially low potential for high current density) still remains a grand challenge. In this study, the fabrication of bismuthene nanosheets using an in‐situ electrochemical transformation strategy of monoclinic scheelite BiVO4 flakes is demonstrated. Catalyzing the CO2 electroreduction in 1 m KHCO3 aqueous solution, the bismuthene nanosheets exhibit a dramatically high formate Faradaic efficiency (FE) of ≈97.4% and a very large current density of −105.4 mA cm−2 at −1.0 V versus reversible hydrogen electrode. Significantly, over a record wide potential window of 750 mV from the initial −0.65 V to the applied minimum −1.4 V, the formate FEs of the bismuthene nanosheets are always higher than 90%, outperforming state‐of‐the‐art electrocatalysts. Both experimental and theoretical investigations reveal that, in comparison with •COOH and H• intermediates, the bismuthene nanosheets preferentially promote fast reaction kinetics towards HCOO•, which eventually accelerates the production of formate.