Oxygen vacancies and Au with plasma resonance jointly tailoring efficient dissociation of excitons to bolster photoreduction CO2 activity

Efficient dissociation of excitons is induced through the combination of O v and plasma effect. • The disruption of electronic structure uniformity in BiOCl leads to a decrease in exciton binding energy. • Photo-induced electrons efficiently migrate to Bi sites adjacent to O v , facilitating subsequent CO 2 reduction. • The introduction of Au and O v help to reduce the energy barrier of rate-determining step, improving reduction rate. Photogenerated carriers are one of the cores of photocatalysis, however, layered structural materials mainly form excitons after being excited by light due to lack of one dimension, while the utilization of excitons is crucial for low-dimensional photocatalysts. Herein, the strong excitonic effect in BiOCl (BOC) can be reduced via photodeposition of Au, accompanied by formation of additional oxygen vacancies (O v ). It can break the uniformity of electronic structure, lower exciton binding energy (E b ) and promote efficient dissociation of excitons into free carriers. Besides, the loading of Au with plasma resonance can dramatically improve light absorption capacity and generate additional electrons. Based on above advantages, as well as analysis through electrochemical testing, fluorescence and Bader charge, it is known that photo-induced electrons efficiently migrate to Bi sites adjacent to O v , increasing electron density and facilitating subsequent CO 2 activation and hydrogenation reduction. Resultly, 0.8%Au/BOC possesses the highest catalytic performance, delivering a CO production rate of 18.7 μmol g −1 , which is 6.2 times the catalytic activity of BOC. By combining advanced characterization and computational modeling, we reveal the introduction of Au and more O v helps to reduce the energy barrier of rate-determining step, and thus improving the reduction rate. Download: Download high-res image (125KB) Download: Download full-size image