Ultrasound-assisted synthesis of a feathery-shaped BiOCl with abundant oxygen vacancies and efficient visible-light photoactivity

A feathery-shaped form of BiOCl (BOC-M) with a high concentration of oxygen vacancies was successfully synthesized using the ultrasound method at room temperature with maltitol as a surfactant. BOC-M was found to exhibit excellent visible-light photocatalytic activities for the degradations of the antibiotic tetracycline hydrochloride (TC-HCl) and rhodamine B (RhB), whose reaction rate was found to be approximately 3 times higher than that using bulk BiOCl (BOC). The enhanced visible photocatalytic performance of BOC-M was ascribed to its high concentration of oxygen vacancies, large specific surface area and strong hydrophilicity. Moreover, the photocatalytic reaction mechanism was further revealed by performing radical- and hole-trapping experiments and electron spin resonance spectroscopy (ESR). The results suggested that ˙O2− was the main active species during the degradation process. This work provided a facile and scalable method to synthesize maltitol-assisted Bi-based photocatalysts and shed light on the highly efficient catalysis offered by BiOCl resulting from the oxygen vacancies produced by the new synthetic route we developed.