Fluorine-doped Bi2O3 derived from metal-organic framework for electrocatalytic CO2 reduction to formate at industrial current densities

Achieving high activity and stability at high current densities is critical in the practical application of electrocatalytic CO2 reduction (ECO2R). In this study, a fluorine-doped Bi2O3 electrocatalyst with oxygen vacancies (denoted as F-Bi2O3-Ov) has been synthesized using a Bi-based metal-organic framework as the sacrificial template. Catalyst characterizations reveal that the fluorine doping induces results in lattice expansion and generates abundant oxygen vacancies. The F-Bi2O3-Ov catalyst delivers a formate Faradaic efficiency of 94% at a current density of 300 mA cm-2 and with stable performance for over 25 h in a flow cell. Electrochemical kinetics analysis and in situ attenuated total reflectance Fourier transform infrared spectroscopy establish a fluorine doping and oxygen vacancies synergy that facilitates interfacial charge transfer, lowering the energy barrier for the formation of the key *OCHO intermediate. The findings of this study offer an effective strategy for modulating the electronic and geometric characteristics of metal oxide catalysts for high-performance ECO2R.