Construction of Inverse–Opal ZnIn₂S₄ with Well–Defined 3D Porous Structure for Enhancing Photocatalytic H₂ Production

The conversion of solar energy into hydrogen using photocatalysts is a pivotal solution to the ongoing energy and environmental challenges. In this study, inverse opal (IO) ZnIn2S4 (ZIS) with varying pore sizes is synthesized for the first time via a template method. The experimental results indicate that the constructed inverse opal ZnIn2S4 has a unique photonic bandgap, and its slow photon effect can enhance the interaction between light and matter, thereby improving the efficiency of light utilization. ZnIn2S4 with voids of 200 nm (ZIS–200) achieved the highest hydrogen production rate of 14.32 μ mol h−1. The normalized rate with a specific surface area is five times higher than that of the broken structures (B–ZIS), as the red edge of ZIS–200 is coupled with the intrinsic absorption edge of the ZIS. This study not only developed an approach for constructing inverse opal multi–metallic sulfides, but also provides a new strategy for enriching efficient ZnIn2S4–based photocatalysts for hydrogen evolution from water.