In-situ construction of Sn-doped BiOCl/Bi2WO6 heterojunction for excellent organic pollutants degradation: Insight into performance and mechanism

Heterojunction formation and metal doping are two prospective strategies for accomplishing efficient separation of charges. However, the photogenerated carriers' separation efficiency still has space for ascension when one of them is utilized alone. In this study, Sn-BiOCl/Bi2WO6 composite was constructed by tin chloride etching to investigate the synergy of heterojunction and metal doping toward the elevated of photogenerated carrier' separation efficiency. The Sn2+/Sn4+ redox couple and heterojunction interface promotes the charges separation and reactive oxygen species (ROS) generation, leading to the Sn-BiOCl/Bi2WO6 exhibits 2.75 and 1.95 times of photodegradation rates towards rhodamine B (RhB) compared to Bi2WO6 and BiOCl/Bi2WO6. Meanwhile, the Sn-BiOCl/Bi2WO6 behaves photocatalytic activation effect on bicarbonate and sulfite to boost excessive ROS generation during the process of photocatalytic degradation of ciprofloxacin (CIP). Furthermore, the possible RhB and CIP photodegradation pathways over Sn-BiOCl/Bi2WO6 were further explored by MS spectra. This study offers a reliable method to develop highly efficient photocatalyst for environmental remediation.