Kinetics of Photocatalytic Degradation of Methylene Blue by TiO₂-Graphene Nanocomposites

Reduced graphene oxide (RGO)/TiO₂ nanocomposite was successfully prepared by UV-assisted photocatalytic reduction of graphene oxide (XGO) by TiO₂ nanoparticles in ethanol. The effects of XGO and RGO addition in TiO₂ were characterized by transmission electron microscopy (TEM), X-ray diffractometer (XRD), diffuse reflectance UV–vis spectrophotometer (UV–vis), fouriertransform infrared spectroscopy (FTIR), photoluminescence (PL), and Brunauer–Emmett–Teller (BET) and Barrett–Joiner–Halenda (BJH) porosity analysis. The photocatalytic activity of prepared nanocomposites was evaluated from the kinetics of the photocatalytic degradation of cationic methylene blue dye under UV irradiation. Bandgap, the electron–hole recombination, specific surface area, surface functional groups, and adsorption capacity of nanocomposites were found to play a significant role in the degradation. The results revealed that RGO/TiO₂ and XGO/TiO₂ nanocomposites exhibited efficient charge separation and enhanced photocatalytic activity, compared to pristine TiO₂. Nearly 500% improvement was observed in this work.