Oxygen vacancies induced narrow band gap of BiOCl for efficient visible-light catalytic performance from double radicals

In this work, a high-efficiency photocatalytic BiOCl material with a visible light absorption range was successfully prepared by one-pot molecular self-assembly and particle recrystallization method at room temperature. In the process of crystal growth, tartaric acid, as a structure control agent, gradually transforms the stacked two-dimensional nano-sheet-like BiOCl into a hierarchical structure composed of petal-like nano-sheets through hydrogen bonding. Besides, the acid etching of organic carboxylic acid on the crystal surface increases the number of micropores and mesopores, thereby the reaction interface. The thiourea (TU) molecules adsorbed on the BiOCl surface with a strong electronic effect introduce oxygen vacancies (OVs) under the condition of low oxygen content. The synergistic effect of hierarchical structure and OVs reduces the recombination of photogenerated carriers, but absorbs more O2 and OH− to generate a large number of superoxide radicals (·O2−) and hydroxyl radicals (·OH) effectively. The photocatalytic performance of the synthesized BiOCl material has been significantly improved, and it can effectively degrade 94.15% of rhodamine B (RhB) within 20 min. Furthermore, 90.95% of tetracycline (TC), 93.76% of ciprofloxacin (CIP), and 85.53% of methyl orange (MO) can be removed in 80 min. Therefore, our work provides an effective method for preparing BiOCl with visible light catalytic activity, which, of course, can be used to treat and repair actual environmental problems under mild conditions.