Regenerative In Situ Formed Bi Nanoparticles on Bi2O2CO3 Nanosheets with Bi-Vacancies for Efficient and Stable Photocatalytic CO2 Reduction to Formate

Abstract

Photocatalytic CO2 reduction to formate suffers from poor productivity, selectivity, stability and recyclability. To conquer these drawbacks, a new facile strategy has been utilized to create regenerative in situ formed Bi0 nanoparticles on Bi2O2CO3 nanosheets for photocatalytic CO2 reduction to formate by taking advantage of the self-photoreduction of Bi3+ to Bi0. It has been proven that Bi0 nanoparticles and Bi vacancies are in situ generated simultaneously and adjacently on Bi2O2CO3 nanosheets under illumination (namely BOC-L) via in situ XPS, PXRD, AC-STEM, and FT-IR. Further mechanistic studies have revealed that the contacted corner between the Bi0 nanoparticle and Bi2O2CO3 matrix serve synergistically as the catalytic center for CO2 conversion to formate, while Bi vacancies boost CO2 adsorption. As an integral result, high productivity (33.5 mmol/gh) and selectivity (99%) have been achieved. Notably, Bi2O2CO3 can be easily regenerated from BOC-L via a wet chemical method and keep the initial productivity with little decline after 55 recycles with 5 hours/cycle. Moreover, the chemically stable Bi2O2CO3 ensures the maintained performance of CO2 conversion to formate even after over two months storage in ambient condition. This work provides a universal approach to construct highly efficient and robust photocatalyst towards desired reactions for practical applications.