Bi₃TiNbO₉/Bi₂S₃ Heterojunction for Efficient Photosynthesis of H₂O₂ in Pure Water

Abstract Heterojunction engineering has been deemed one of the most promising strategies for promoting charge separation and improving solar‐to‐chemicals efficiency. Howbeit, constructing well‐defined nanoheterojunction with superior photocatalytic activity for H₂O₂ generation and a clear reaction mechanism remains a formidable challenge. Herein, an in situ vulcanization way to synthesize an intriguing 2D/1D Bi₃TiNbO₉/Bi₂S₃ heterojunction by growing Bi₂S₃ nanorods on Bi₃TiNbO₉ microsheet is used for the first time, where an S‐scheme charge transfer mechanism is formed that facilitates the spatial separation of charge carriers. Moreover, the in situ grown Bi₂S₃ on Bi₃TiNbO₉ can optimize the interfacial electronic structure and the reaction energy barriers. As a result, the H₂O₂ yield rate for Bi₃TiNbO₉/Bi₂S₃ can reach 810(2) µmol g⁻¹ h⁻¹ without any sacrificial agents and cocatalysts, ≈6.18 and ≈18.0 times of pristine Bi₃TiNbO₉ and Bi₂S₃, respectively. Importantly, the heterojunction unveiled unprecedented stability, remaining ≈95.46(2)% of the initial one after 13 continuous cycles. This work highlights an innovative in situ vulcanization strategy to engineer oxide perovskite/metal sulfide nanocomposite catalysts for artificial photosynthesis of H₂O₂, opening new opportunities for achieving highly efficient photocatalyst systems.