In situ self-growing 3D hierarchical BiOBr/BiOIO3 Z-scheme heterojunction with rich oxygen vacancies and iodine ions as carriers transfer dual-channels for enhanced photocatalytic activity

A 3D hierarchical BiOBr/BiOIO3 Z-scheme heterojunction with rich oxygen vacancies and iodine ions was successfully synthesized via in situ solvethermal method and it was used to effectively remove heavy metal mercury. Combining experimentation and characterization, it was discovered that Z-scheme heterojunction and the local surface plasmon resonance (LSPR) effect to construct dual-channels for charge carrier transferring that not only accelerate the separation and transfer efficiency of electron-hole pairs, but also maintain high redox reaction capacity. Meanwhile, the unique 3D hierarchical structure can improve the adsorption capacity and widen the light response range. Moreover, comparative experiments prove that the coordination of Z-scheme heterojunction and oxygen vacancy promotes molecular oxygen activation to generate more ROS (·O2– and ·OH), which is further beneficial for the photocatalytic activity. As a result, BiOBr/BiOIO3 highest photocatalytic removal of heavy metal mercury under visible light can achieve 90.25%. This study provides a new direction to design efficient photocatalysts for promising solar utilization and environmental purification.