Photocatalytic Reduction of Chromium(VI) in Wastewater by Ag/WO3/rGO Nanocomposite under Visible Light Irradiation

Abstract

Under visible light irradiation, a photocatalytic reduction of hexavalent chromium (Cr(VI)) in wastewater was demonstrated using an Ag/WO3/rGO nanocomposite. The nanocomposite was created using a hydrothermal technique. The integration of Ag nanoparticles and rGO nanosheets into the WO3 structure resulted in increased porosity and roughness, as well as enhanced active sites on the surface of the nanocomposite, which can improve the effective surface area, according to structural analyses using XRD and SEM. Based on UV–vis absorption spectra, the optical band-gaps of WO3, Ag/WO3, and Ag/WO3/rGO nanocomposite were predicted to be 2.89, 2.80, and 2.59 eV, respectively. Electrochemical investigations revealed that the Ag/WO3/rGO nanocomposite exhibited a lower electrochemical resistance to charge transfer than WO3 and Ag/WO3, indicating efficient charge transportation and decreased photo-generated carrier recombination kinetics. Photocatalytic analyses revealed that after 120, 95, and 80 minutes of visible light irradiation, respectively, 90 percent removal efficiency of Cr(VI) ions was obtained, whereas complete removal of WO3, Ag/WO3, and Ag/WO3/rGO nanocomposite was obtained after 155, 130, and 120 minutes of visible light irradiation, respectively. The practical ability of Ag/WO3/rGO nanocomposite to reduce Cr(VI) in prepared genuine samples of industrial wastewater was examined, and the results demonstrated the suggested photocatalyst's efficient performance in reducing Cr(VI) in industrial wastewater