The overpotential and selectivity of electrochemical CO₂ reduction over metal electrodes are closely related to the adsorption strength of key intermediate. Defect engineering of the materials can modulate the energetic difference between the antibonding states and the Fermi level, thus strengthening the surface-adsorbate chemical bonds and boosting the steady progress of the electrochemical reaction. Here, we proposed an efficient strategy to electrochemically reduced layered Bi₂O₂CO₃ to Bi nanosheet with (001) dominant facet and atom vacancies. The Bi nanosheet exhibits 90% CO₂-to-formate Faradaic efficiency at a low overpotential of 420 mV and excellent stability over 100 h in 0.1 M KHCO₃ electrolyte. Spectroscopic and computational studies confirm that the Bi atom vacancies induced the electron-rich surface, leading the movement of p states towards the Fermi level, hence decreasing the activation energy of CO₂ to CO₂-* radical and promoting the stability of OCHO* intermediate via p orbitals hybridization between the O in carbon-containing intermediates and the Bi electrode.

金属电极上电化学CO ₂还原的过电势和选择性与关键中间体的吸附强度密切相关。材料的缺陷工程可以调节反键态与费米能级之间的能量差，从而增强表面吸附物的化学键并促进电化学反应的稳定进行。在这里，我们提出了一种有效的策略，以电化学方式将层状Bi ₂ O ₂ CO ₃还原为具有（001）主晶面和原子空位的Bi纳米片。Bi纳米片在420 mV的低过电势下表现出90％的CO _2形成法拉第效率，并且在0.1 M KHCO _3中100 h内具有出色的稳定性。电解质。光谱和计算研究证实，Bi原子空位诱导了富电子表面，从而导致p态向费米能级移动，从而降低了CO ₂转化为CO _2- *自由基的活化能并提高了OCHO *中间体的稳定性通过含碳中间体中的O与Bi电极之间的p轨道杂交。