Synthesis and characterization of novel WO3 loaded Ag–ZnO and its photocatalytic activity

A novel WO3 loaded Ag–ZnO photocatalyst was successfully synthesized by a simple solvothermal method and characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) images, energy dispersive spectrum (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV) and Brunauer–Emmett–Teller (BET) surface area measurements. The photocatalytic activity of WO3–Ag–ZnO was investigated for the degradation of RR 120 and RO 4 dyes in aqueous solution using UV-A light. WO3–Ag–ZnO is found to be more efficient than Ag–ZnO, WO3–ZnO, Ag–WO3, commercial ZnO, prepared ZnO, TiO2-P25 and TiO2 (Merck) at neutral pH for the mineralization of dyes. First time we have reported that novel WO3 loaded Ag–ZnO has been found to be very efficient for two azo dyes removal when compared to commercially available catalyst (Degussa P25, ZnO (Merck) and TiO2 (Merck)). The mineralization of dyes has been confirmed by chemical oxygen demand (COD) measurements. A mechanism of degradation has been proposed for the higher efficiency of WO3–Ag–ZnO.

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► A novel WO3 loaded Ag–ZnO was prepared by a simple solvothermal method.
► ‘Ag’ traps the electron from both ZnO and WO3 reducing electro–hole recombination.
► WO3–Ag–ZnO is more efficient than Ag–ZnO, WO3–ZnO, Ag–WO3 and undoped catalysts.
► WO3–Ag–ZnO material will be much useful for the treatment of dye effluents.