Enhanced Catalytic Activity of TiO2/rGO Nanocomposites with Squaraine Dye for Photocatalytic Wastewater Treatment

Wastewater treatment has stimulated researchers to develop highly efficient catalysts for the degradation of organic pollutants. The present work focuses on the design and investigation of a titanium dioxide (TiO2)-based photocatalytic system with improved catalytic ability under visible light. TiO2/reduced graphene oxide (TiO2/rGO) and squaraine dye (SQ) sensitized TiO2/rGO (TiO2/rGO/SQ) composites were synthesized by a facile solvothermal method. The incorporation of SQ aims to enhance the photocatalytic efficiency of the synthesized composites and extend their activity by utilizing the visible-light spectrum. The composite materials were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), the Brunauer–Emmett–Teller (BET) surface area analysis, and UV–Vis diffuse reflectance spectroscopy (DRS). The synthesized composites were evaluated for the decolorization of the organic dyes Rhodamine B (RhB) and Fluorescein (FL) in aqueous solutions. The synthesized composites were evaluated for the decolorization of the organic dyes Rhodamine B (RhB) and fluorescein (FL) in aqueous solution. Under visible-light irradiation, TiO2/rGO/SQ achieved 98% decolorization of FL and 86% decolorization of RhB within 180 min.