Enhanced photocatalytic performance of WO3 loaded Ag–ZnO for Acid Black 1 degradation by UV-A light

The WO3 loaded Ag–ZnO (WO3-Ag–ZnO) was successfully synthesized by solvothermal method. The catalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) images, transmission electron microscope (TEM) images, energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV) and BET surface area measurements. The photocatalytic activity of WO3-Ag–ZnO was investigated for the degradation of Acid Black 1 (AB 1) 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 (bare) ZnO, TiO2-P25 and TiO2 (Merck) at pH 9 for the mineralization of AB 1. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of AB 1 have been analyzed. The mineralization of AB 1 has been confirmed by COD measurements. The catalyst is found to be reusable.

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► The WO3-Ag–ZnO was successfully synthesized by a simple solvothermal method.
► Electron and hole transfer between two oxides makes this catalyst more photoactive.
► ‘Ag’ metal acts as electron trapper reducing electron–hole recombination.
► WO3-Ag–ZnO composite catalyst will be much useful for the treatment of dye effluents.