Fabrication and photocatalysis of TiO2-graphene sandwich nanosheets with smooth surface and controlled thickness

Abstract TiO 2 -graphene sandwich nanosheets (TG) with smooth surface and controlled thickness were prepared by a two-step process. First, TiO 2 -Graphene oxide (GO) nanosheets (TGO) were prefabricated via the controllable hydrolysis of tetrabutyl titanate in ethanol/water suspension of graphene oxide. The sandwich structure of TGO with smooth surface was confirmed by AFM, XPS and XRD. And the thicknesses of TGO varied from 3.4 nm to 36.0 nm when the weight ratio of TiO 2 /GO changed from 1.0 to 20.0. Followed by calcination under Ar at 400 °C, the sandwich structures were well preserved and their thicknesses still showed a linear correlation with the weight ratio of TiO 2 /GO. Meanwhile, the amorphous TiO 2 on GO was crystallized into anatase and GO was reduced to graphene. Photocatalytic activity of TG was carried out by the degradation of Rhodamine B. It rose first and then fell with the thickness of TG increasing, and TG with thickness of ∼9 nm showed the best of all. Our work not only provides a promising route to fabricate graphene based two-dimensional nanomaterials, but also provides a prerequisite to study the influence of nanosheet thickness on their physical and chemical properties.