Surface Local Polarization Induced by Bismuth-Oxygen Vacancy Pairs Tuning Non-Covalent Interaction for CO₂ Photoreduction

The inefficient charge separation and lack of active sites have been regarded as the main obstacles limiting the CO₂ photoreduction efficiency. It is highly desirable but challenging to create a local polarization field to accelerate charge separation and build reactive sites for CO₂ reduction dynamics. Herein, atomic level bismuth-oxygen vacancy pairs are engineered into Bi₂₄O₃₁Br₁₀ (BOB) atomic layers to create a local polarization field. It facilitates photogenerated electrons to migrate from BOB to vacancy pair sites and favors the activation of CO₂ molecules. Simultaneously, it works as reactive sites to tune the non-covalent interaction of intermediates and optimizes the reaction process. The vacancy pairs tuned surface atomic structures enable the formation of a highly stable Bi−C−O−Bi intermediate state and consecutive Bi−C−O intermediate, thus changing the rate-determining step from CO* formation to COOH* formation. Benefiting from these features, the V_BiO-BOB delivers a 20.9-fold CO₂ photoreduction activity enhancement relative to highly crystalline BOB in pure water with highly stability. This work provides new insights for the design of a vacancy pair to create local polarization and tune the non-covalent interaction.