Metal Ce-Leaching Induced Structural Optimization of Bismuth Electrocatalyst for Enhanced CO2 Electroreduction

The direct utilization of CO2 by electroreduction is a promising route to achieve valuable chemicals and realizing a negative carbon cycle. Nanostructured Bi-based materials have attracted large attention due to their multiple advantages, however, the influence of metal leaching in modulating their catalytic performance remains unclear. Herein, metal Ce is taken as a typical example to study the structural and performance regulation of a Bi2O3-derived electrocatalyst for CO2 reduction. The postcharacterizations prove the leaching of Ce metal sites during in situ electroreduction and the formation of active crystal plane of the Ce leaching-derived Bi nanosheets (CLD-Bi Ns). As a result, the Faradaic efficiency (FE) of formate maintains over 95% in a wide potential range of −0.5 to −1.0 V for the CLD-Bi Ns catalyst, along with a high current density of 272.6 mA cm–2 at −0.8 V versus RHE in a flow cell. The in situ FT-IR confirms the appearance of key *OCHO species with continuously applied potentials, and the DFT calculation demonstrates the optimized free energy of *OCHO and *HCOOH intermediates on the (012) plane of CLD-Bi Ns sample, resulting in the improved catalytic performance. This work provides an effective and promising strategy to improve the catalytic performance of other materials for CO2 electroreduction.