Rational design, synthesis, and application of silica/graphene-based nanocomposite: A review

Graphene, which has good electrical/thermal conductivity, excellent mechanical properties and large specific surface area, is promising in various fields. However, the easy aggregation of graphene limits its application. Silica, including mesoporous silica, has potential applications in many fields due to its characteristics of good chemical stability, easy modification, high-temperature resistance and low cytotoxicity. The combination of the two exciting materials to form silica/graphene (SiO2/G) composites not only overcomes the aggregation problem but also leads to enhanced or even new physical/chemical properties and high performance due to their synergic effects. Designing and constructing a reasonable structure of SiO2/G composite material is vital for its practical application. In this review, the synthesis strategy of SiO2/G-based composites is highlighted. This strategy includes growing silica layers on graphene nanosheets to form sandwich structures, growing silica spheres on graphene nanosheets, and wrapping graphene layers on silica spheres. This review focuses on the superior application of the nanocomposites in the fields of energy storage, catalysis, environmental protection, biomedicine and polymer composites. Furthermore, the challenges and the new future research directions of these emerging nanocomposites are provided.