Spatial charge separated two-dimensional/two-dimensional Cu-In₂S₃/CdS heterojunction for boosting photocatalytic...

Two-dimensional (2D) beta indium sulfide (β-In₂S₃) shows great potential in photocatalytic hydrogen production due to its broad-spectrum response, relatively negative conduction band edge, high carrier mobility and low toxicity. However, the high charge recombination rate limits the application of In₂S₃. Here, we in-situ grew 2D cadmium sulfide (CdS) on the surface of In₂S₃ doped with copper ions (Cu²⁺) to construct a heterojunction photocatalyst that suppresses charge recombination. The in-situ grown method and shared sulfur composition were conducive to forming the efficient interface contact between In₂S₃ and CdS, promoting charge transfer and showing the high spatial charge separation rate, resulting in a hydrogen production rate of 868 µmol g^-1h^-1. The induced Cu²⁺ extended the light absorption range and stabilized the photocatalyst. By creating stable 2D/2D heterojunction photocatalysts with high charge separation efficiency, this work opens new possibilities for applying In₂S₃ materials in photocatalytic hydrogen production.