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.

Automated summary

By engineering atomic level bismuth-oxygen vacancy pairs into Bi24O31Br10 (BOB) atomic layers, a local polarization field is created to facilitate charge separation and CO2 activation. The tuned surface atomic structures enable the formation of stable intermediates, leading to an enhanced CO2 photoreduction efficiency. This work provides new insights for the design of vacancy pairs to optimize the reaction process and improve catalytic activity.