Interfacial engineering of bismuth sulfide/oxychloride heterostructure for boosting the conversion from CO2 to formate at large current densities

Electrochemical reduction of CO2 into green fuels is considered as a promising strategy to achieve carbon neutrality and has received increasing attentions. Herein, bismuth sulfide-bismuth oxychloride heterojunctions (Bi2S3-BiOCl) with abundant hetero-interface are rational synthesized and used as electrocatalysts for CO2 reduction reaction. The high formate selectivity of 97.2% at large current density of 300 mA cm-2 can be easily achieved. The in situ Raman spectroscopy and ex situ characterizations indicate that BiOCl converts to metallic Bi at negative potential to form a Bi2S3-Bi heterojunction. Based on the theoretical calculations, Bi2S3-Bi shows increasing density of states around the Fermi level and decreased energy barrier for CO2 conversion, and eventually promots electrocatalytic CO2 reduction reaction. This work not only provides an in-depth study of the application of Bi-involved heterojunctions for CO2 conversion, but also proposes a new strategy for the devel-opment of efficient catalysts for industrial-level CO2 conversion.

Automated summary

In this study, bismuth sulfide-bismuth oxychloride heterojunctions were synthesized and used as electrocatalysts for CO2 reduction reaction, achieving high formate selectivity of 97.2% at a large current density. The conversion of BiOCl to metallic Bi at negative potential forms a Bi2S3-Bi heterojunction, which increases the density of states around the Fermi level and decreases the energy barrier for CO2 conversion, promoting the electrocatalytic CO2 reduction reaction. This work not only provides an in-depth study of the application of Bi-involved heterojunctions for CO2 conversion, but also proposes a new strategy for the development of efficient catalysts for industrial-level CO2 conversion.