In Situ Construction of Bi₁₂O₁₇Cl₂/Bi₂S₃ S-Scheme Heterojunctions with Enriched Oxygen Vacancies to Enhance Photocatalytic Activity

The construction of S-scheme heterojunctions with oxygen vacancies (OVs) is an effective strategy to enhance the photocatalytic activity. In this pioneering study, we successfully fabricated Bi12O17Cl2/Bi2S3 S-scheme heterojunctions with abundant OVs (ROV-BOC/BS) using an anion exchange method. The in situ growth of Bi2S3 (BS) nanorods on OVs-rich Bi12O17Cl2 (ROV-BOC) nanosheets resulted in an interconnected reticulated structure. This structure not only increased the specific surface area of the composite but also established a tightly bound heterojunction, further enhancing the OVs content in the composites. The OVs-induced defect levels provide additional channels for photogenerated charge migration. The synergy between the heterojunction and OVs improved the light absorption and carrier separation efficiency. Consequently, the optimized ROV-BOC/BS-0.1 achieved 95.52% Cr(VI) removal efficiency within 120 min, with apparent reaction rate constants 5.39 and 23.86 times higher than those of pure ROV-BOC and BS, respectively. This investigation provides crucial guidance for designing novel S-scheme heterojunction photocatalysts with abundant OVs.