Synthesis of layer-like Ni(OH)2 decorated ZnIn2S4 sub-microspheres with enhanced visible-light photocatalytic hydrogen production activity

Abstract

Novel layer-like Ni(OH)₂ co-catalyst-decorated ZnIn₂S₄ microsphere photocatalysts were synthesized for the first time via a facile in situ deposition method to boost the photocatalytic H₂-production performance. The physical and optical properties of the as-prepared Ni(OH)₂–ZnIn₂S₄ composite samples were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffusion reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and surface photovoltage spectroscopy (SPV). The results indicate that the photocatalytic H₂ evolution activity of the ZnIn₂S₄ microspheres under visible light irradiation significantly enhances by introducing inexpensive Ni(OH)₂ as a co-catalyst. The 5 mol% Ni(OH)₂–ZnIn₂S₄ sample shows the highest H₂-production rate of 8.35 mmol g⁻¹ h⁻¹, which is 18 times higher than that of pure ZnIn₂S₄. Moreover, photocatalytic activity of the Ni(OH)₂–ZnIn₂S₄ sample remains stable even after 4 cycling photocatalytic experiments. In addition, a possible mechanism on the enhanced photocatalytic activity was proposed and verified by surface photovoltage spectroscopy.