Highly selective electrocatalytic reduction of CO2 to HCOOH over an in situ derived Ag-loaded Bi2O2CO3 electrocatalyst

Abstract

The electrochemical reduction of CO₂ to HCOOH is considered one of the most appealing routes to alleviate the energy crisis and close the anthropogenic CO₂ cycle. However, it remains challenging to develop electrocatalysts with high activity and selectivity towards HCOOH in a wide potential window. In this regard, Ag/Bi₂O₂CO₃ was prepared by an in situ electrochemical transformation from Ag/Bi₂O₃. The Ag/Bi₂O₂CO₃ catalyst achieves a faradaic efficiency (FE) of over 90% for HCOOH in a wide potential window between −0.8 V and −1.3 V versus the reversible hydrogen electrode (RHE). Moreover, a maximum FE of 95.8% and a current density of 15.3 mA cm⁻² were achieved at a low applied potential of −1.1 V. Density functional theory (DFT) calculations prove that the high catalytic activity of Ag/Bi₂O₂CO₃ is ascribed to the fact that Ag can regulate the electronic structure of Bi, thus facilitating the adsorption of *OCHO and hindering the adsorption of *COOH. This work expands the in situ electrochemical derivatization strategy for the preparation of electrocatalysts.