Accelerating proton relay via fluorine-modified bismuth for efficient carbon dioxide electroreduction to formate.

Regulating the dissociation of interfacial water to govern the proton supply for hydrogenating critical intermediates is an effective strategy to improving the catalytic activity and product selectivity of the carbon dioxide (CO2) reduction reaction. Herein, we report a fluorine-doped bismuth nanosheet catalyst (F-Bi NS), synthesized through the in-situ electrochemical reconstruction of a Bi-trifluoroethylamine complex. F-Bi NS exhibits exceptional selectivity toward formate (>90%) across a broad pH range. Theoretical calculations reveal that F doping effectively modulates the electronic structure of Bi active sites, enhances the adsorption and activation of interfacial H2O molecules, and provides a proton supply for the hydrogenation of adsorbed CO2 to produce the *OCHO intermediate. These effects collectively lower the reaction energy barrier, thereby boosting both the activity and selectivity for formate generation. Furthermore, by coupling CO2 reduction with glycerol oxidation, efficient and synergistic production of formate was achieved in a two-electrode system, demonstrating the potential of coupled electrocatalytic strategies for the simultaneous synthesis of multiple value-added chemicals.