Sulfur boosting CO2 reduction activity of bismuth subcarbonate nanosheets via promoting proton-coupled electron transfer

Bismuth (Bi) based nanomaterials are attractive catalysts for electrochemical CO2 reduction to formate, while both high selectivity and high activity still need further investigation. Herein, we report a facile strategy, via introducing sulfur (S) atoms to modulate the electronic structure of two-dimensional (2D) bismuth subcarbonate Bi2O2CO3 (BiOC) nanosheets, to improve their catalytic activity meanwhile maintain high formate selectivity. The lower electronegativity of the substituted S than O enhances the local electron density around Bi active sites, promoting the proton-coupled electron transfer to the CO2 intermediate, and thus contributing to the superior CO2 reduction performance with the selectivity of formate >90% in a wide negative potential range and high partial current density up to 29.0 mA cm-2 at -0.9 vs RHE. This study provides an in-depth understanding on the design of advanced CO2 reduction electrocatalysts via heteroatom doping.

Automated summary

This study presents a facile strategy to improve the catalytic activity of two-dimensional bismuth subcarbonate nanosheets for electrochemical CO2 reduction to formate by introducing sulfur atoms and modulating the electronic structure. The doping of sulfur enhances the local electron density around bismuth active sites, promoting proton-coupled electron transfer and contributing to superior CO2 reduction performance with high formate selectivity.