Loading iridium (Ir) single atoms on hierarchical ZnIn2S4 architectures: Unveiling heterojunction-driven photocatalytic enhancement towards organic dye degradation

In this study, Ir-loaded hierarchy ZnIn2S4 (ZIS) nanoparticles are synthesized via a hydrothermal method. The hierarchy of ZIS nanoparticles exhibits flower-like morphology. Ir atoms are deposited uniformly on the surface of the ZIS nanoparticles. The interaction between ZIS and Ir is evidenced by the shift in the XPS peak of Ir. According to the UV-Vis spectrum and Tauc plots, loading Ir atoms onto ZIS leads to a decreased bandgap and enhanced visible light absorption. The degradation of RhB and MO indicates that the photocatalytic efficiency of the ZIS/Ir composite is 2.8–3.6 times that of the bare ZIS. This change can be attributed to the heterojunction between Ir and ZIS, resulting in faster charge transfer, more effective charge separation, and a longer lifetime of charge carriers. This study demonstrates that creating a heterojunction between the semiconductor photocatalyst and the single metal atoms is an effective strategy to increase photocatalytic efficiency. •ZnIn2S4 hierarchical particles were synthesized via a hydrothermal method.•Ir single atoms were uniformly deposited on the surface of ZnIn2S4 nanoparticles.•The heterojunction between Ir and ZnIn2S4 was confirmed by XPS analysis.•ZnIn2S4 /Ir composites exhibited significantly enhanced photocatalytic activity.