In situ fabrication of 2D Bi/Bi2O2CO3 nanosheets anchored on Bi substrate for highly-efficient photoelectrocatalytic CO2 reduction to formate

Abstract

Utilizing photoelectrocatalysis for the CO2 conversion into value-added chemicals presents a promising approach for alleviating energy-environmental crisis, but the current catalysts encounter the limitations of electron transfer efficiency, activity and stability. Herein, we in situ construct Bi/Bi2O2CO3 composite film with nanosheets anchored on Bi substrate to optimize reaction kinetics, and effectively enhance the separation and transport efficiencies of photogenerated carriers. Our findings reveal that the formate Faraday efficiency of 92.68 % at −0.95 V (vs. RHE) for photoelectrocatalytic CO2 reduction over Bi/Bi2O2CO3 film is much higher obviously than 84 % of electrocatalytic CO2 reduction reaches, and there is no significant decrease within 10 h of activity test. Besides, the highest applied bias photon-to-current efficiency and cathode energy efficiency can achieve 1.19 % and 61 %, respectively, indicating the superior energy utilization of the catalyst. Finally, a reasonable electron transfer mechanism for the enhanced photoelectrocatalytic CO2 reduction over Bi/Bi2O2CO3 film is proposed and clarified based on the spectral characterizations and density functional theory calculations. This work should provide a novel perspective for the design and research of Bi-based photocathodes.