Selective CO2 Electroreduction to Formate on Polypyrrole‐Modified Oxygen Vacancy‐Rich Bi2O3 Nanosheet Precatalysts by Local Microenvironment Modulation

Abstract

AbstractChallenges remain in the development of highly efficient catalysts for selective electrochemical transformation of carbon dioxide (CO2) to high‐valued hydrocarbons. In this study, oxygen vacancy‐rich Bi2O3 nanosheets coated with polypyrrole (Bi2O3@PPy NSs) are designed and synthesized, as precatalysts for selective electrocatalytic CO2reduction to formate. Systematic material characterization demonstrated that Bi2O3@PPy precatalyst can evolve intoBi2O2CO3@PPy nanosheets with rich oxygen vacancies (Bi2O2CO3@PPy NSs) via electrolyte‐mediated conversion and function as the real active catalyst for CO2 reduction reaction electrocatalysis. Coating catalyst with a PPy shell can modulate the interfacial microenvironment of active sites, which work in coordination with rich oxygen vacancies in Bi2O2CO3 and efficiently mediate directional selective CO2 reduction toward formate formation. With the fine‐tuning of interfacial microenvironment, the optimized Bi2O3@PPy‐2 NSs derived Bi2O2CO3@PPy‐2 NSs exhibit a maximum Faradaic efficiency of 95.8% at −0.8 V (versus. reversible hydrogen electrode) for formate production. This work might shed some light on designing advanced catalysts toward selective electrocatalytic CO2 reduction through local microenvironment engineering.