Synthesis and Characterization of Titania−Graphene Nanocomposites

Abstract

In this work, the synthesis and physiochemical characterization of titanium oxide nanoparticle−graphene oxide (TiO2−GO) and titanium oxide nanoparticle−reduced graphene oxide (TiO2−RGO) composites was undertaken. TiO2−GO materials were prepared via the hydrolysis of TiF4 at 60 °C for 24 h in the presence of an aqueous dispersion of graphene oxide (GO). The reaction proceeded to yield an insoluble material that is composed of TiO2 and GO. Composites were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, N2 adsorption−desorption, and thermal gravimetric analysis/differential thermal analysis (TGA/DTA). This approach yielded highly faceted anatase nanocrystals with petal-like morphologies on and embedded between the graphene sheets. At higher GO concentrations with no stirring of the reaction media, a long-range ordered assembly for TiO2−GO sheets was observed due to self-assembly. GO−TiO2 composites formed colloidal dispersions at low concentrations (∼0.75 mg/mL) in water and ethanol but were not amenable to forming graphene papers via filtration through Anodisc membranes (0.2 μM pore diameter) due to their high titania concentration. Zeta potential measurements and particle size distributions from dynamic light scattering (DLS) experiments on these materials explain the stability of the TiO2−GO colloidal solutions. Chemical and thermal methods were also used to reduce TiO2−GO to give TiO2−RGO materials.