Effective shuttling of photoexcitons on CdS/NiO core/shell photocatalysts for enhanced photocatalytic hydrogen production

Abstract

Hierarchical structure of NiO immobilized on CdS photocatalyst (CdS/NiO) was synthesized for stable and efficient H2 production. The catalyst is designed to suppress the photo-corrosion behaviour without affecting catalytic activity of CdS structures having tamarind leaf-like morphology is protected by fabricating thin-layer of NiO. The exterior thin-layer transmits the light into CdS in-turn exciton moved to surface for reaction with adsorbed reactant species. Structural, morphological and optical properties were studied using X-ray diffraction (XRD), ultraviolet-visible light (UV–vis) diffuse reflectance spectra (DRS), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS). The results illustrates that synthesized catalyst composed of crystalline CdS/NiO hierarchical structure that absorbs light in the visible spectrum and improved charge carrier separation than CdS or NiO alone. The photocatalytic activity was examined for H2 generation under visible light irradiation using Xe-lamp as light source. In order to achieve enhanced H2 production rate amount of NiO loading was optimized and results were found in the following order CdS/NiO > CdS. Under optimal conditions the catalyst showed stable H2 evolution for 30 h of continuous irradiation. Under optimal conditions catalyst showed visible light to H2 conversion efficiency of 6.63%.