Porous spherical indium oxide-loaded BiOIO3 nanosheets to construct Z-scheme heterojunction to enhance photocatalytic activity

In this work, In2O3/BiOIO3 Z-scheme heterojunction composites enriched with oxygen vacancies were prepared by hydrothermal and calcination methods. Combining the experimental results with DFT calculations, it is found that the photogenerated electrons of In2O3-loaded BiOIO3 are transferred along the Z-scheme path, which proves that the In2O3/BiOIO3 Z-scheme heterojunction is successfully synthesized. The introduction of In2O3 has resulted in abundant oxygen vacancies on the surface of the composites. Oxygen vacancies construct new carrier transfer channels to accelerate the separation and transfer efficiency of electron-hole pairs. The photocatalytic activity was evaluated by the removal efficiency of the heavy metal mercury in the gas phase. The best sample had a Hg removal efficiency of 98.5 %. Finally, we propose that the synergistic interaction of oxygen vacancies and Z-scheme heterojunction promotes the activation of molecular oxygen and the generation of more ROS (·O2- and·OH) with high redox reactivity and analyze the mechanism in detail.