Affiliation:
1. Hefei National Research Center for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy Conversion Department of Materials Science and Engineering University of Science and Technology of China Hefei Anhui 230026 China
2. Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China
Abstract
AbstractBismuth‐based materials have emerged as promising catalysts in the electrocatalytic reduction of CO2 to formate. However, the reasons for the reconstruction of Bi‐based precursors to form bismuth nanosheets are still puzzling, especially the formation of defective bismuth sites. Herein, we prepare bismuth nanosheets with vacancy‐rich defects (V‐Bi NS) by rapidly reconstructing Bi19Cl3S27 under negative potential. Theoretical analysis reveals that the introduction of chlorine induces the generation of intrinsic electric field in the precursor, thereby increasing the electron transfer rate and further promoting the metallization of trivalent bismuth. Meanwhile, experimental tests verify that Bi19Cl3S27 has a faster reconstruction rate than Bi2S3. The formed V‐Bi NS exhibits up to 96 % HCOO− Faraday efficiency and 400 mA cm−2 HCOO− partial current densities, and its electrochemical active surface area normalized formate current density and yield are 2.2 times higher than those of intact bismuth nanosheets (I‐Bi NS). Density functional theory calculations indicate that bismuth vacancies with electron‐rich aggregation reduce the activation energy of CO2 to *CO2− radicals and stabilize the adsorption of the key intermediate *OCHO, thus facilitating the reaction kinetics of formate production.
Funder
National Natural Science Foundation of China