Z-scheme BiOCl/Bi–Bi2O3 heterojunction with oxygen vacancy for excellent degradation performance of antibiotics and dyes

Researchers have begun to pay close attention to the construction of artificial Z-scheme photocatalysts due to their excellent ability to separate photogenerated electron–hole pairs and prominent redox ability. In this study, Bi-bridged Z-scheme BiOCl/Bi2O3 (BiOCl/Bi–Bi2O3) heterojunctions with oxygen vacancies were prepared via a one-step hydrothermal method. The phase structure, morphology, and optical properties of the samples were characterized using XRD, XPS, ESR, FESEM, HRTEM, and UV–Vis DRS. Compared with BiOCl and Bi–Bi2O3, the prepared BiOCl/Bi–Bi2O3(25% and 50%) samples exhibited enhanced photocatalytic activity in degrading colorless antibiotics (tetracycline hydrochloride) and colored dyes (RhB) under visible light irradiation. This result indicated improved visible light absorption due to the presence of oxygen vacancies and enhanced separation efficiency of the photogenerated electron–hole pairs and high redox ability due to the construction of the Z-scheme. On the basis of the results of radical-trapping, photoelectron chemical experiments, and PL analysis, a possible photocatalytic mechanism of the Z-scheme BiOCl/Bi–Bi2O3 heterojunctions was proposed.