Metal–Organic Layers Leading to Atomically Thin Bismuthene for Efficient Carbon Dioxide Electroreduction to Liquid Fuel

Abstract Electrochemical reduction of CO 2 to valuable fuels is appealing for CO 2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide potential window is challenging. Herein, atomically thin bismuthene (Bi‐ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth‐based metal–organic layers. The few‐layer Bi‐ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm −2 without compromising selectivity in a flow‐cell reactor. Using in situ ATR‐IR spectra and DFT analysis, a reaction mechanism involving HCO 3 − for formate generation was unveiled, which brings new fundamental understanding of CO 2 reduction.