RESUMO
In this study, graphene oxide (GO) sheets were successfully synthesized using two routes: conventional Hummers' (HGO) and modified Hummers' (or Marcano's) (MGO) methods. GO sheets were then assembled with TiO2 nanoparticles to form nanocomposites (i.e., HGO-TO and MGO-TO). The properties of HGO and MGO and their nanocomposites with TiO2 were evaluated by Fouriertransform infrared (FTIR), Raman, ultraviolet-visible (UV-Vis) adsorption, and diffuse reflectance (DRS) spectroscopies, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The specific surface area, pore volume, and pore size of MGO, determined by Brunauer-Emmett-Teller (BET) equation, were 565 m²g-1, 376 cm³ g-1, and 30 nm, respectively; all of these parameters decreased after MGO was combined with TiO2. In addition, compared with HGO, MGO possessed higher oxidation level and more stable bonding with TiO2 nanoparticles. The morphology of HGO and MGO, which were characterized by scanning electron (SEM) and transmission electron microscopies (TEM), together with energy-dispersive X-ray (EDX) spectroscopy and elemental mapping technique, was determined to consist of TiO2 nanoparticle-assembled GO sheets. All GO-TiO2 nanocomposite samples exhibited a very high activity (Ë100%) toward rhodamine B (RhB) dye photodegradation under natural sunlight exposure within 60 min. The obtained results for the GO-TiO2 nanocomposite showed the potential of its application in wastewater purification and other environmental aspects.
