Highly Efficient 2D/3D Structured CuCo₂S₄/CdIn₂S₄ Composites with a p–n Heterojunction for Boosting Photocatalytic Hydrogen Evolution

Constructing novel surface microstructures for photocatalytic materials could significantly enhance the photocatalytic hydrogen production rate from water splitting. In this work, novel 2D/3D structured CuCo2S4/CdIn2S4 p–n heterojunction photocatalysts for water splitting were successfully prepared by a solvothermal method. The coupling of a 2D CuCo2S4 nanoplate on the surface of 3D flower-like CdIn2S4 microspheres has strengthened the visible light absorption and promoted the charge separation efficiency due to their tight contacting area. The obtained CuCo2S4/CdIn2S4 (CSCIS-2) photocatalyst exhibited a hydrogen production rate of 1320 μmol g–1 h–1, which was fivefold of that for pure CdIn2S4. Additionally, cyclic tests demonstrated improved photoactivity stability of the samples. A series of photoelectrochemical characterizations confirmed the effective suppression of charge carrier recombination in CuCo2S4/CdIn2S4 composite catalysts. Finally, a rational photocatalytic mechanism was proposed based on the semiconductor band theory. This work contributes to the enrichment of sulfide-based research and applications in photocatalysis.