Enhanced CO2 photoreduction over bismuth-rich Bi4O5Br2: Optimized charge separation and intrinsic barriers

Abstract

Photocatalytic CO2 conversion into chemicals is one of effective strategies to overcoming the energy crisis and global warming. However, the CO2 photoreduction efficiency is hindered by poor charge separation and CO2 activation. The composition regulation of photocatalyst is a promising strategy to solve these issues. Herein, we constructed the Bi4O5Br2 in ionic liquid through a solvothermal approach. The electronic structure of photocatalyst has been regulated over Bi4O5Br2 through Bi-rich strategy, achieving enhanced charge separation and long carrier lifetime. Density-functional theory (DFT) calculations found that the intrinsic barriers for CO2 adsorption-activation can be effectively optimized over Bi4O5Br2, promoting the CO2 dissociation and facilitating the generation of *COOH. Therefore, Bi4O5Br2 possesses improved evolution rates of 23.81 and 1.33 μmol g−1 for CO and CH4 under irradiation of 300 W Xe lamp for 4 h. This work demonstrates a valuable strategy for the rational construction of efficient materials towards CO2 photoreduction.