The Controllable Reconstruction of Bi‐MOFs for Electrochemical CO2 Reduction through Electrolyte and Potential Mediation

Monitoring and controlling the reconstruction of materials under working conditions is crucial for the precise identification of active sites, elucidation of reaction mechanisms, and rational design of advanced catalysts. Herein, a Bi‐based metal–organic framework (Bi‐MOF) for electrochemical CO2 reduction is selected as a case study. In situ Raman spectra combined with ex situ electron microscopy reveal that the intricate reconstruction of the Bi‐MOF can be controlled using two steps: 1) electrolyte‐mediated dissociation and conversion of Bi‐MOF to Bi2O2CO3, and 2) potential‐mediated reduction of Bi2O2CO3 to Bi. The intentionally reconstructed Bi catalyst exhibits excellent activity, selectivity, and durability for formate production, and the unsaturated surface Bi atoms formed during reconstruction become the active sites. This work emphasizes the significant impact of pre‐catalyst reconstruction under working conditions and provides insight into the design of highly active and stable electrocatalysts through the regulation of these processes. The reconstruction of Bi‐MOFs prior to CO2 electroreduction can be decoupled into two steps: 1) electrolyte‐mediated conversion of Bi‐MOFs to Bi2O2CO3 by HCO3−‐initiated ligand substitution, and 2) potential‐mediated reduction of Bi2O2CO3 to Bi. The first step controls the final morphology and structure, whilst the second step determines the final composition and valence states.