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.