Influence of Dopant Concentration on the Photocatalytic Activity of PVA/ZnO:Fe/ZnS Nanocomposites

Abstract— In this work, one PVA/ZnO:Fe sample and five PVA/ZnO:Fe/ZnS nanocomposites with varying Fe doping concentrations were successfully synthesized via a chemical precipitation method using polyvinyl alcohol (PVA) as the capping agent. The structural, morphological, compositional, and optical properties of the synthesized samples were investigated using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray analysis (EDAX), Transmission Electron Microscopy (TEM), UV-visible Spectroscopy, Photoluminescence (PL) Spectroscopy and Fourier Transform Infrared (FTIR) Spectroscopy. The characterization results confirmed the successful formation of the PVA/ZnO:Fe and PVA/ZnO:Fe/ZnS nanocomposites and demonstrated that Fe doping significantly influences their structural and optical properties. The photocatalytic performance of the synthesized nanocomposites was evaluated through the visible-light-driven degradation of methyl orange (MO). The results revealed that the incorporation of the ZnS shell, together with appropriate Fe doping, markedly enhanced the photocatalytic activity compared with PVA/ZnO:Fe. The optimum nanocomposite exhibited a maximum degradation efficiency of 95.97% toward MO under visible light irradiation, demonstrating its potential as an efficient visible-light-responsive photocatalyst for wastewater treatment applications.