In<sub>2</sub>O<sub>3</sub> Nanoparticle/Bi<sub>4</sub>O<sub>5</sub>Br<sub>2</sub> Nanosheet S-Scheme Heterojunctions with Interfacial Oxygen Vacancies for Photocatalytic Degradation of Tetracycline
Xi Zhang, Xin Zha, Yu Luo, Tiantian Liu, Guoning Chen, Xipu He
Abstract
The development of highly efficient photocatalysts for antibiotics contamination in water remains a severe challenge. In this study, In 2 O 3 nanoparticle/Bi 4 O 5 Br 2 nanosheet S-scheme heterojunction with interface oxygen vacancies (OVs) was constructed by a hydrothermal-calcination approach and a simple chemical precipitation process. Under simulated sunlight, this composite showed enhanced degradation efficiency for tetracycline hydrochloride (TCH) with 92.4%, which was much higher than those of pure Bi 4 O 5 Br 2 (50.2%) and In 2 O 3 (28.6%). The excellent removal efficiency was mainly attributed to the synergistic effect of S-scheme heterojunctions and interface OVs accelerating the complexation of unwanted electrons (e – ) and holes (h + ), thus retaining e – with the strong oxidizing ability and h + with the strong reducing ability to participate in the reaction. In addition, the abundant OVs in In 2 O 3 nanoparticles/Bi 4 O 5 Br 2 nanosheets could enhance the adsorption of O 2 and promote the generation of superoxide radicals (·O 2 – ). The toxicity of the tetracycline degradation products and the catalyst was evaluated by E. coli growth inhibition experiments. Based on the TCH intermediates detected by HPLC-MS, three possible TCH degradation pathways were proposed. This study shows that the construction of S-scheme heterojunctions with interfacial defects is an effective strategy for the preparation of efficient photocatalysts.