Bi4O5BrI Solid Solution towards Boosted Photocatalytic Reduction and Oxidation Activities Induced by Efficient Carrier Separation

Semiconductor photocatalysis is considered a promising technology for destroying pollutants, while the faint carrier separation efficiency of the photocatalyst is one of the main limitations for obtaining high performance. This study reports a solid solution strategy to achieve effective carrier separation in Bi 4 O 5 Br x I 2− x . The solid solution structure endows Bi 4 O 5 Br x I 2− x with proper light adsorption, tunable band gap, and effective separation of photogenerated electrons and holes. As a result, Bi 4 O 5 Br x I 2− x exhibits reduction and oxidation activities for highly efficient photocatalytic Cr(VI) reduction and tetracycline hydrochloride (HTC) degradation under visible light irradiation, with the activity reaching the maximum at x = 1. Within 30 min, the removal rates of Cr(VI) and HTC reach 90% and 100%, respectively. This study not only provides an effective strategy to increase the carrier separation of bismuth-based semiconductors, but also opens new opportunities to rationally design other solid solution catalysts with high performance in wastewater treatment.