Improved Photocatalytic Performance of Cobalt Doped ZnS Decorated with Graphene Nanostructures under UV-visible Light: Towards Efficient H2 Production

Abstract

Highly dispersed Cobalt doped ZnS nanostructures were successfully fabricated on the surfaces of graphene sheets via a simple hydrothermal method. X-ray diffraction (XRD), X-ray photocurrent spectroscopy (XPS), Raman spectroscopy (RS), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were utilized to analyze the structural characteristics of the Cobalt doped ZnS decorated with graphene CoxZn1−xSrGO Nanostructures (NSs). UV-visible optical absorption (UV-vis) studies were conducted to investigate their optical properties. In laboratory studies utilizing water and visible light, the photocatalytic activity of CoxZn1−xS rGO NSs at (x = 0, 1, 2, 4 and 6 atm.%) were evaluated. Graphite Oxide (GO) was successfully transformed in to sheets of graphene, according to the findings of XRD and FTIR analysis. SEM investigation showed graphene sheets enhanced with ZnS NSs possessed paper like appearance. UV-vis confirmed a noticeable rapid increase in transmittance along the UV wavelength area and confirmed a highly transparent NSs in the wavelength range of (180-800 nm). Transmittance spectra revealed a direct allowable band gap range of (1.26-5.46 eV), demonstrating band gap decrease as cobalt content increased. The Co0.04Zn0.96S rGO NSs sample had the highest photocatalytic activity, measured at 7649 μmolh−1g−1. A combination of improved dispersion properties, greater surface area, increased absorption and enhanced transfer of photogenerated electrons, CoxZn1−xS rGO NSs increased the photocatalytic hydrogen H2 generation activity.