Construction of core-shell Bi4O5Br2 structure for efficient photocatalytic CO2 reduction

Limited light absorption and low carrier separation efficiency remain major obstacles to converting CO 2 into solar fuel. Rational design of semiconductor photocatalysts with unique structures holds promise for overcoming these challenges. In this study, Bi 4 O 5 Br 2 photocatalyst with a hollow core-shell architecture is synthesized via a one-step solvothermal method. This innovative structure facilitates efficient reflection and absorption of incident light within its internal cavity, while also minimizing the charge transfer path. Consequently, it significantly improves both light harvesting capabilities and charge carrier separation efficiency. Compared to the solid Bi 4 O 5 Br 2 (CO, 0.21 μmol g −1 h −1 ; CH 4 , 0.78 μmol g −1 h −1 ) and hollow Bi 4 O 5 Br 2 (CO, 0.25 μmol g −1 h −1 ; CH 4 , 0.99 μmol g −1 h −1 ) counterparts, the hollow core-shell Bi 4 O 5 Br 2 exhibits superior CO 2 photoreduction performance, achieving production rates of 3.61 and 2.40 μmol g −1 h −1 for CO and CH 4 , respectively. Notably, it also enhances C 2 H 4 production during the CO 2 reduction process, with a yield of 0.17 μmol g −1 h −1 , whereas no detectable C 2 H 4 is produced by either the solid or hollow Bi 4 O 5 Br 2 structures. This research provides fresh insights into the structural design of advanced photocatalysts and holds significant implications for converting CO 2 into high-value chemicals.