Anion Exchange Facilitates the In Situ Construction of Bi/BiO Interfaces for Enhanced Electrochemical CO2‐to‐Formate Conversion Over a Wide Potential Window

Abstract

AbstractElectrochemical reduction of CO2 (CO2RR) into value‐added products is a promising strategy to reduce energy consumption and solve environmental issues. Formic acid/formate is one of the high‐value, easy‐to‐collect, and economically viable products. Herein, the reconstructed Bi2O2CO3 nanosheets (BOCR NSs) are synthesized by an in situ electrochemical anion exchange strategy from Bi2O2SO4 as a pre‐catalyst. The BOCR NSs achieve a high formate Faradaic efficiency (FEformate) of 95.7% at −1.1 V versus reversible hydrogen electrode (vs. RHE), and maintain FEformate above 90% in a wide potential range from −0.8 to −1.5 V in H‐cell. The in situ spectroscopic studies reveal that the obtained BOCR NSs undergo the anion exchange from Bi2O2SO4 to Bi2O2CO3 and further promote the self‐reduction to metallic Bi to construct Bi/BiO active site to facilitate the formation of OCHO* intermediate. This result demonstrates anion exchange strategy can be used to rational design high performance of the catalysts toward CO2RR.