Abstract: In this work, a novel Bi₂S₃/Bi₅O₇I p-n heterojunction with three-dimensional rod-like nanostructure was successfully constructed through an in-situ topotactic ion exchange approach. A possible evolution mechanism from Bi₅O₇I nanobelts (NBs) into Bi₂S₃/Bi₅O₇I rod-like heterostructures (BSI RHs) was proposed, depicting the self-assembly process of internal Bi₅O₇I NBs and outside networks interwoven by Bi₂S₃ nanorods (NRs), which abided by the Ostwald ripening and epitaxial growth. Owing to the formation of p-n heterojunction and rich oxygen vacancies (OVs), the visible-light absorption ability and separation of photogenerated charge carriers of BSI RHs were highly promoted, leading to a greatly improved photocatalytic ability than that of Bi₂S₃ and Bi₅O₇I. BSI-1 exhibited the strongest photocatalytic performance, and almost all rhodamine B (RhB) and Pseudomonas aeruginosa (P. aeruginosa) can be thoroughly removed within 90 min. Moreover, a possible photocatalytic mechanism of BSI RHs was proposed based on the tests of active species trapping, electron spin resonance (ESR), photoelectrochemistry (PEC), and photoluminescence (PL) combined with the density functional theory (DFT) simulated computation, validating the dominating roles of · O₂^- and h⁺ during the photocatalytic process. This work is expected to motivate further efforts for developing novel heterostructures with highly efficient photocatalytic performances, which presents a promising application prospect in the fields of energy and environment.

Key words: Antifouling, Bi₅O₇I, Photocatalytic, Heterostructure, Bi₂S₃