Noncovalently Functionalized Graphene-Directed Synthesis of Ultralarge Graphene-Based TiO2 Nanosheet Composites: Tunable Morphology and Photocatalytic Applications

Abstract

Ultralarge graphene-based TiO2 nanosheet composites are successfully fabricated by a noncovalent functionalization approach with use of benzyl alcohol as the linking agent. In the synthetic procedure, the aromatic molecules of benzyl alcohol direct themselves onto graphene (GR) surface via π–π interaction. Therefore, the basal planes of GR nanosheets are uniformly functionalized with hydroxyl groups derived from benzyl alcohol, which not only improves the dispersion of GR in solution but also induces a finely homogeneous coating of TiO2 nanocrystals onto the surface of GR nanosheets. The resulting GR@TiO2 nanocomposites, which feature unique ultralarge 2D sheet-like morphology with the lateral size far larger than the original GR and densely interfacial contact, are able to act as highly active photocatalysts toward selective reduction of aromatic nitro compounds to amines in water under ambient conditions. The higher photoactivity of GR@TiO2 than blank TiO2 is attributed to the efficient charge carriers separation and transfer by the GR platform. It is hoped that the facile synthesis strategy in this work could contribute to fabricating other ultralarge functional GR-based 2D sheet-onto-sheet composites with tunable morphology toward target photocatalytic applications.