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

Abstract

The use of TiO2/graphene composites as catalysts for photodegradation of dyes has been widely investigated. TiO2/graphene composites are usually obtained by coating TiO2 on the surface of pre‐prepared graphene. However, graphene is prone to curling and stacking, which makes it difficult to uniformly coat TiO2 on its surface, resulting in poor photocatalytic performance. In this paper, a non‐conventional approach to prepare TiO2/graphene nanocomposites based on the use of porous SiO2/graphene spheres as supports is presented. SiO2/graphene spheres with intercalated structure and dendritic pores were prepared as supports by a one‐step hydrothermal method. Then, TiO2 was coated into the pores of SiO2/graphene spheres by sol‐gel method to obtain SiO2/graphene@TiO2 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.