Synthesis of SiO2/Graphene@TiO2 Composites for the Visible Light Photocatalytic Degradation of Wastewater

Abstract The use of TiO 2 /graphene composites as catalysts for photodegradation of dyes has been widely investigated. TiO 2 /graphene composites are usually obtained by coating TiO 2 on the surface of pre‐prepared graphene. However, graphene is prone to curling and stacking, which makes it difficult to uniformly coat TiO 2 on its surface, resulting in poor photocatalytic performance. In this paper, a non‐conventional approach to prepare TiO 2 /graphene nanocomposites based on the use of porous SiO 2 /graphene spheres as supports is presented. SiO 2 /graphene spheres with intercalated structure and dendritic pores were prepared as supports by a one‐step hydrothermal method. Then, TiO 2 was coated into the pores of SiO 2 /graphene spheres by sol‐gel method to obtain SiO 2 /graphene@TiO 2 composites (SGT). After 90 min of visible light irradiation, the degradation rate of RhB by SGT catalyst was 68.9 %, which was significantly higher than that of P25 by 39.3 %. A mechanism of the RhB removal by the SGT composites was proposed.