Synergistic effect of TiO2-rGO nanocomposites with Fenton's reagent for the enhanced photocatalytic degradation of nitrophenols in solar light.

In the present study, Graphene Oxide (GO) was prepared by the modified Hummer's method. Further, different wt% of reduced Graphene Oxide (rGO) decorated TiO2 (TiO2-rGO) nanocomposites were synthesized using non-toxic sodium L-ascorbate as a reducing agent. The structure, morphology, optical and chemical composition of the composites were investigated with analytical techniques such as XRD, FESEM, HRTEM, UV –Vis DRS, FTIR, XPS and Raman spectroscopy. The zeta potential study reveals that the surface charge of the materials is negative and the value increases with the increase in the rGO content which proves residual acid groups on rGO and by the decoration of rGO surface with TiO2. The photocatalytic activity of the composites was tested for the degradation of nitrophenols [Mononitrophenol (MNP), Dinitrophenol (DNP) and Picric Acid (PA)] in the presence of the Fenton's reagent with UV light (wavelengths 254 and 390 nm), visible light and sunlight at different pHs (3,7 and 10). In the presence of Fenton's reagent, the catalyst TiO2-rGO 1% exhibited 100% degradation of nitrophenols in UV light of wavelength 254 nm within 15 min whereas with sunlight the catalysts, TiO2-rGO 5% and TiO2-rGO 10% exhibited 100% degradation of nitrophenols within 15 min and 18 min, respectively, at pH 3. Thus, the combined catalysts could have much impact on the photocatalytic degradation of water-borne organisms in the future. [ABSTRACT FROM AUTHOR]