Synthesis of Graphene oxide-TiO2 nanocomposites and determination of their photocatalytic activities under simulated, direct and concentreated sun light

GO was prepared from graphite powder by the modified Hummers method and nitrogen doped titanium dioxide and non-doped titanium dioxide nanoparticles were synthesized by sol-gel method. GO:N-TiO2 and GO-TiO2 nanocomposites were synthesized through low temperature hydrotermal process. Characterization of the synthesized samples were done by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy and BET analysis techniques. Photodegradation of Rhodamine B dye was tested with GO, TiO2, N-TiO2, GO-TiO2 and GO:N-TiO2 catalysts under simulated sun light, i.e Xe-lamp, direct and concentrated sun light. Intensity of concentrated sun light was ~10 and ~390 folds of direct and simulated sun light, respectively. Although the degradation rate constants have differed, GO:N-TiO2 nanocomposites exhibited the highest photocatalytic activity. This situation is attributed to the red shift observed in absorption region after nitrogen doping and to the formation of Ti-O-C bond in GO, TiO2 composite.