Heteroatom Doping Modulates the Electronic Environment of Bi for Efficient Electroreduction of CO2 to Formic Acid

Electrocatalytic reduction reaction of carbon dioxide (CO2RR) to formic acid is widely considered an effective strategy for addressing the greenhouse effect and enhancing energy conversion efficiency. However, existing catalytic systems are severely hampered by insufficient activity and significant hydrogen evolution reaction (HER), which substantially compromises the selectivity and stability of CO2RR, necessitating the development of highly efficient and stable electrocatalysts. Herein, we present a heteroatomic modification strategy to synthesize B-doped Bi and N-doped Bi electrocatalysts, and systematically investigate the regulation mechanism of incorporated elements on the electronic environment using X-ray absorption fine structure (XAFS) spectroscopy and other characterization techniques. The optimized B-doped Bi catalyst demonstrates exceptional catalytic performance, achieving a remarkable Faradaic efficiency of 95% for formic acid production at a high current density of -190 mA/cm2 under alkaline conditions, while maintaining excellent stability for 20 h. Through comprehensive experimental characterization and theoretical calculations, we reveal that the B-doping-induced electron-rich structure significantly promotes CO2 molecule activation and facilitates the formation of the key intermediate *OCHO, thereby achieving high selectivity and stability in CO2RR. This work not only elucidates the crucial role of electronic environment in CO2 electrocatalytic conversion but also provides innovative insights into the rational design of high-performance electrocatalysts.