Tuning Optical and Electronic Property via M-S-Si (M = Zn, In) Interface Charge Mediator in ZIS/DFNS for Efficient Reductive Water Splitting under Visible Light Irradiation

The present study describes the synthesis of a novel ZnIn₂S₄/DFNS (ZIS/DFNS) through a hydrothermal method, featuring a spherical morphology. The synthesized DFNS (dendritic fibrous nanosilica) mesoporous silica spheres display a distinctive fibrous structure and uniform distribution. Characterization of the ZIS/DFNS nanocomposites confirms the presence of ZIS and amorphous SiO₂. The material exhibits notable optoelectronic properties and charge separation by forming an M-S-Si (M = Zn, In) interface, making it suitable for photocatalytic hydrogen production under visible light. 20%ZIS/DFNS nanocomposite alone achieves a hydrogen generation of 5770.54 µmol g⁻¹. However, when combined with Pt as a co-catalyst, the hydrogen generation significantly increases to 9887.84 µmol g⁻¹ over 5 h, using Na₂S and Na₂SO₃ as a hole scavenger. This enhancement is due to DFNS's exceptional light-harvesting ability, which results from multiple light-scattering events, as well as the efficient dispersion of ZIS on its fibrous surface. This dispersion enhances water diffusion and interaction with active catalytic sites. This study provides a novel perspective on developing advanced photocatalytic systems by integrating ZIS nanomaterials, which possess an optimal bandgap of 3.1 eV for photocatalytic water splitting, with DFNS, known for its high light-harvesting capability due to its fibrous structure and increased surface area.