Hydrothermal preparation of P25–graphene composite with enhanced adsorption and photocatalytic degradation of dyes

Abstract

Graphene, a 2-D carbon material, has unique electrical properties and high specific surface area. In recent years, carbon materials were impregnated into TiO2 photocatalysts and become a research focus since the pure TiO2 has limited adsorption and photocatalytic ability. In this study, P25–graphene (GN) nanocomposite photocatalyst was prepared by hydrothermal methods. The reduction of graphene oxide and loading of TiO2 (Degussa P25) on GN were completed at the hydrothermal process. By controlling the amount of P25 and the concentration of graphene oxide dispersions, P25–graphene composite with different graphene content was prepared. The nanocomposites were characterized using TEM, XRD, N2 adsorption/desorption analyzer, UV–vis DRS and TGA. As graphene content increasing, the absorption intensity of visible light and the specific surface area was increased. The results showed that P25–graphene composite has better adsorption capacity and photocatalytic degradation efficiency for MB (methylene blue) and RBk5 (reactive black 5) dyes removal. For 10mgL−1 MB, the adsorption removal efficiency can reach above 90% with P25–10% GN dosage of 0.4gL−1. The saturated adsorption capacity of MB is 50mgg−1 under the same condition. For 10mgL−1 RBk5, the degradation removal efficiency can reach more than 90% with 365nm UV light irradiation.