Enhanced visible-light photocatalytic degradation of tetracycline by a novel hollow BiOCl@CeO2 heterostructured microspheres: Structural characterization and reaction mechanism.

A high-efficiency hollow BiOCl@CeO2 heterostructured microspheres with type-II staggered-gap type was successfully synthesized by precipitation-hydrothermal process loaded with BiOCl nanoparticles on CeO2 microspheres. XRD, FT-IR, EDS, SEM, HRTEM and XPS results show that the prepared materials have good crystallization, morphology and retain hollow spherical structure of CeO2. Batch experiments indicate that the photocatalytic performance of BiOCl@CeO2 towards Tetracycline (TC) is superior to pure BiOCl or CeO2 owing to the distinctive hollow structures and the formed heterostructure between BiOCl and CeO2. Cyclic experiment exhibits that the optimal BiOCl@CeO2 photocatalyst can still photodegrade more than 80% of TC in 120 min after 4 cycles. Additionally, the reactive oxidation species (ROS) trapping experiments reveal that the critical ROS include photogenerated holes (h+) and superoxide radical anions (O2-). Finally, the possible degradation pathways of TC and enhanced photodegradation mechanism was systematically discussed. On this basis, the hollow BiOCl@CeO2 heterostructured microspheres provide a new alternative with great potential in efficient visible-light-driven photodegradation of persistent organic pollutants.