Orthogonal test design for preparation of TiO2/Graphene composites and study on its photocatalytic activity

An one-step hydrothermol method was developed to synthesize TiO 2 /Graphene composites (TiO 2 /GR) by employing graphene oxide and tetra-n-butyl titanate. The factors affecting the photocatalytic activity of TiO 2 /GR were studied by using orthogonal design, and the optimum conditions are: reaction temperature 180 °C, reaction time 16 h and pH value 3.0. TiO 2 /GR was characterized on crystal structure, particle size, morphology and specific surface area by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET analysis. The results show that the TiO 2 in composites is anatase and the average diameter is about 18 nm. The BET specific surface area of the TiO 2 /GR is 170 m 2 /g and the average pore diameter is 12.45 nm. Under visible light (λ > 420 nm), the photodegradation of RhB by TiO 2 /GR indicates that the best photocatalytic activities is observed with TiO 2 /GR, compared to P25 and bare TiO 2 obtained by the same conditions.