Synergetic adsorption and photocatalytic degradation of pollutants over 3D TiO2–graphene aerogel composites synthesized via a facile one-pot route

Abstract

A series of composites consisting of anatase TiO₂ nanocrystals and three-dimensional (3D) graphene aerogel (TiO₂–GA) were self-assembled directly from tetrabutyl titanate and graphene oxides via a one-pot hydrothermal process. TiO₂ was found to uniformly distribute inside the 3D network of GA in the resulting composites with large surface areas (S_BET > 125 m² g⁻¹) and high pore volumes (V_p > 0.22 cm³ g⁻¹). In comparison with GA and TiO₂, the composites possessed much higher adsorption capacities and visible light photocatalytic activity in the degradation of rhodamine B (RhB). With an initial concentration of 20.0 mg L⁻¹ of RhB, the adsorptive decolourization of RhB was as high as 95.1% and the total decolourization value reached up to 98.7% under visible light irradiation over 5.0 mg of the resulting composites. It was elucidated that the physical and chemical properties of the TiO₂–GA composites could be ascribed to their unique 3D nanoporous structure with high surface areas and the synergetic activities of graphene nanosheets and TiO₂ nanoparticles.