Construction of Z-scheme Fe3O4/BiOCl/BiOI heterojunction with superior recyclability for improved photocatalytic activity towards tetracycline degradation

The development of recyclable photocatalysts with enhanced photo-induced charge separation and efficient visible light utilization is imperative for antibiotic pollutants removal in aqueous environment. Herein, a Z-scheme Fe3O4/BiOCl/BiOI heterojunction photocatalyst was constructed using a facile solvothermal method on the basis of BiOCl/BiOI composites. A series of characterization methods were employed to analyze the microstructure, morphology, optical property and chemical composition of as-prepared ternary Fe3O4/BiOCl/BiOI composite. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) analysis revealed that Fe3O4 nanoparticles were well loaded on the surface of BiOCl/BiOI microspheres. The main active species of Fe3O4/BiOCl/BiOI during photocatalysis were confirmed by radical trapping experiments, which indicated the formation of Z-scheme heterojunction. Compared to pure BiOCl and BiOI, Fe3O4/BiOCl/BiOI nanocomposite exhibited significantly improved photocatalytic performance toward tetracycline (TC) degradation (89%, 80 min). Furthermore, the photocatalytic activity of Fe3O4/BiOCl/BiOI remained at a high level after five cycles, which suggested that the ternary composite possessed good stability and reusability. Such superior photocatalytic activity of Fe3O4/BiOCl/BiOI was mainly attributed to the suitable band structure and construction of Z-scheme heterojunction, resulting in the enhanced light utilization and migration rate of charge carriers. In addition, Obviously, the ternary composite revealed a potential prospect in the practical application of photocatalytic degradation due to its good magnetic recovery performance and minimal environmental impact.