Fabrication of a visible-light In₂S₃/BiPO₄ heterojunction with enhanced photocatalytic activity

The construction of a heterojunction is an effective way to improve the photocatalytic activity of a semiconductor. In this study, to improve the photocatalytic activity of BiPO₄ in visible light and the quantum yield of In₂S₃, a novel In₂S₃/BiPO₄ heterojunction photocatalyst was successfully synthesized via a solvothermal method. XRD and TEM characterizations reveal that In₂S₃ was irregularly loaded on the surface of BiPO₄, leading to good dispersion of In₂S₃, greatly improving the catalyst active site. Meanwhile, In₂S₃ also greatly improves the visible light absorption of BiPO₄. An ESR spin-trap technique and trapping experiments on active species indicate that O₂^- and h⁺ are the main activated species during the photodegradation process. Finally, the as-obtained In₂S₃/BiPO₄ heterojunction exhibits higher photocatalytic activity than those of pure In₂S₃ and BiPO₄ for the photodegradation of rhodamine B (RhB) and tetracycline (TC). This work provides a promising way to photodegrade organic materials to reduce water pollution.