Functionalization of TiO2 with graphene quantum dots for efficient photocatalytic hydrogen evolution

Abstract Graphene quantum dots (GQDs) serve as a novel solid-state electron transfer reagent anchored on TiO 2 by in situ photo-assisted strategy and greatly enhanced photocatalytic H 2 evolution activity in methanol aqueous solution without the noble mental cocatalyst. The excellent photocatalytic activities were ascribed to the GQDs which act as an excellent electron transporters and acceptors, as well as photosensitizer. GQDs not only acted as efficient electron reservoirs and a solid-state electron transfer reagent from the conduction band of TiO 2 to GQDs, but also acted as an excellent photosensitizer to sensitize TiO 2 , in which the photoinduced electrons transfer from excited GQDs to TiO 2 to produce H 2 . In addition, GQDs is nanoscale fragments of graphene which can provide a larger active surface and greatly increase the contact area with the TiO 2 , which is conducive to rapidly transfer photo-generated electrons due to the large specific area and high carrier mobility of GQDs. Thus, GQDs improved the photocatalytic activity for H 2 evolution.