Synthesis and Characterization of Ag2S Doped Tio2 Nanocatalysts for the Photocatalytic Degradation of Methylene Blue Dye Under UV Light Irradiation

Abstract

The Ag₂S – TiO₂ nanocatalysts were effectively synthesized using the precipitation–thermal decomposition method. Characterization of the prepared catalyst was conducted through X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), Energy dispersive spectra (EDS), Ultra-violet diffuse reflectance spectra (UV-DRS), Photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) measurements. The photocatalytic activity of
Ag₂S – TiO₂ was examined for the deterioration of Methylene blue (MB) dye in aqueous solution under UV-A light. Ag₂S – TiO₂ demonstrated superior effectiveness compared to other photocatalysts (ZnO, Ag₂S, TiO₂, etc.) at pH 7 for MB dye mineralization. The effect of operational parameters including photocatalyst amount, dye concentration, and initial pH on MB dye photomineralization was analyzed. Active species trapping revealed the significant roles of holes, electrons, hydroxyl radicals, and superoxide radicals in the photocatalytic deterioration of MB dye. A proposed mechanism for dye deterioration using Ag₂S – TiO₂ was elucidated. Mineralization of MB dye was further confirmed through Chemical Oxygen Demand measurements. The catalyst exhibited reusability. Additionally, antibacterial activity evaluation revealed that Ag₂S – TiO₂ showed potential as an effective antibacterial agent.