Chemically reduced graphene oxide (RGO) can be functionalized by eosin Y (EY). The formation of the stable aqueous EY functionalized graphene (EY-RGO) suspension is due to the non-covalent interaction between EY and RGO surface via hydrogen bonding and pi-pi stacking. EY-RGO was characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Spectral and photoelectrochemical studies indicate that photoinduced electron transfer occurs from EY to RGO. The EY-RGO is photocatalytic active for water reduction to produce hydrogen. The average production rate of H-2 for the photocatalyst (w(Ey)/w(RGo) = 1) in a 10 vol % triethanolamine aqueous solution can reach 3.35 mmol g(-1) h(-1) and 0.40 mmol g(-1) h(-)1 under 30 h UV-vis and 10 h visible light irradiation, respectively. The photocatalytic activity of EY-RGO is superior to that of RGO, graphene oxide (GO), and EY-GO. Modification EY-RGO with Pt nanoparticles can further improve photocatalytic activity. All these features demonstrated that organic sensitizers functionalized graphene provided a nice candidate as a photocatalyst for H-2 generation from water under solar light irradiation. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.