Synthesis and Characterization of Titania-Graphene Nanocomposites

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 degrees C for 24 h in the presence of air 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, N-2 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 (similar to 0.75 mg/mL) in water and ethanol but were not amenable to forming graphene papers via filtration through Anodisc membranes (0.2 mu M 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.