Tuning microenvironment of Bi2O3 nanosheets via Ce doping for promoting CO2 electrolysis to formate

Abstract

The precise tuning of the electrocatalytic surface microenvironment for CO2 adsorption and conversion is essential for an efficient electrocatalytic CO2 reduction reaction (eCO2RR); however, it constitutes a challenging task. In this work, Ce-doped Bi2O3 nanosheets with enhanced Bi oxidation and abundant oxygen vacancies have been developed as an efficient electrocatalyst for the eCO2RR. The synthesized Ce/Bi2O3 nanosheet electrocatalyst achieves a Faraday efficiency above 90 % for formate production within a wide potential window from −0.8 to −1.1 V (versus RHE). The Ce dopant as an electron acceptor modifies the electronic structure of the Bi sites, enhancing the CO2 adsorption and promoting the formation of CO2•−. Moreover, Ce doping provides a local high pH and accelerates the proton-electron transfer process of *OCHO intermediates. This work provides new insights into the formation of a highly active reaction zone at the gas–liquid–solid interface for establishing a favorable microenvironment and further promoting an efficient eCO2RR.