Graphene quantum dots (GQDs) serve as a novel solid-state electron transfer reagent anchored on TiO₂ by in situ photo-assisted strategy and greatly enhanced photocatalytic H₂ 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 TiO₂ to GQDs, but also acted as an excellent photosensitizer to sensitize TiO₂, in which the photoinduced electrons transfer from excited GQDs to TiO₂ to produce H₂. In addition, GQDs is nanoscale fragments of graphene which can provide a larger active surface and greatly increase the contact area with the TiO₂, 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 H₂ evolution.