Regulating the Oxygen Vacancy on Bi2MoO6/Co3O4 Core‐Shell Nanocage Enables Highly Selective CO2 Photoreduction to CH4

Abstract

AbstractPhotocatalytic CO2 reduction reaction (CO2RR) into high‐value‐added fuels has received significant attention, yet multiple electron and proton processes involved in CO2RR result in low selectivity. Herein, a strategy involving oxygen vacancies (Ovs)‐enriched Bi2MoO6 coated on ZIF‐67‐derived Co3O4 to construct well‐defined core‐shell nanocage is developed, which drives effective CO2 photoconversion to CH4 with nearly 100% selectivity and high apparent quantum efficiency of 2.5% at 420 nm in pure water under simulated irradiation. Theoretical calculations and experiments exhibit that the potential difference stemming from the built‐in electric field provides guarantee for CO2 reduction occurring on Bi2MoO6 and H2O oxidation set in Co3O4. Numerous exposed Bi2MoO6 with Ovs formed in Bi─O bond by ethylene glycol mediated approach promotes the CO2 adsorption and charge separation efficiency, which can optimize the reaction kinetics and thermodynamics, facilitating the hydrogenation of key intermediate *CO to generate CH4. This work provides a new strategy for controlled oxygen vacancy generation on photocatalysts to achieve high‐performance CO2 methanation.