Effects of TiO2 content on the microstructure, mechanical properties and photocatalytic activity of three dimensional TiO2-Graphene composite prepared by hydrothermal reaction

A series of three dimensional (3D) porous TiO2-graphene (TGR) hydrogel samples with different mass ratio of graphene to TiO2 were obtained using a one-step hydrothermal method. Their microstructure, mechanical properties, and photocatalytic activity were investigated. The TGR samples exhibited well defined interconnected 3D porous network microstructure and good mechanical strength. Moreover, the pore size and the compressive strength could be easily adjusted by changing the content of TiO2, showing a decreasing tendency with the increase of the relative content of TiO2. The results of the photodegradation of methylene blue indicated that the photocatalytic activity of the TGR samples can be significantly enhanced, compared to the pure TiO2 nanoparticles. The TGR sample also showed good durability and reusability. The mechanisms resulting in the improvement of photocatalytic activity were investigated with DRS, PL spectra, and adsorption experiment under dark conditions. It was found that adsorption is the dominant factor for the enhanced photocatalytic activity.