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

Abstract 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 Bi4O5BrxI2−x. The solid solution structure endows Bi4O5BrxI2−x with proper light adsorption, tunable band gap, and effective separation of photogenerated electrons and holes. As a result, Bi4O5BrxI2−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.