Photodegradation of two dyes, methylene blue (MB) and rhodamine B (RB), adsorbed over composites of TiO2 nanoparticles with pure graphene as well as boron-and nitrogen-doped graphenes has been investigated. MB which is a good electron donor and has a low ionization energy interacts strongly with electron-deficient boron-doped graphene resulting in fast degradation of the dye. On the other hand, RB which is not such a good electron donor and has a higher ionization energy, interacts strongly with electron-rich nitrogen-doped graphene causing a faster degradation of the dye. (C) 2011 Elsevier B. V. All rights reserved.