Preparation and photocatalytic activity of graphene/nano TiO₂ composites

Using graphene oxide (GO) and tetrabutyl orthotitanate (Ti(OBu)₄) as raw materials, the graphene/nano TiO₂ composites were synthesized via a solvothermal reaction in ethanol solvent. The crystal structure, morphology and element form of graphene/nano TiO₂ composites were characterized by XRD, FE-SEM, TEM, RAMAN and XPS. And the photocatalytic activity of graphene/nanoTiO₂ composites was investigated by the photocatalytic degradation of methyl orange in aqueous solution. The results show that Ti(OBu)₄ molecules are uniformly grafted on GO by chemisorption in ethanol solvent, both of the reduction of GO and deposition of anatase TiO₂ nanoparticles on GO are achieved during the solvothermal process. With prolongation of solvothermal reaction, the content of active groups on GO quickly decreases, so GO is reduced more firmly. Meanwhile, the size of TiO₂ crystal particles increases with the prolongation of solvothermal reaction. Compared to pure TiO₂, the graphene/nano TiO₂ composites exhibit higher photocatalytic activity, and the graphene ratios in composites have direct impact on the photocatalytic activity.