A LDA plus U study of the hybrid graphene/anatase TiO2 nanocomposites: Interfacial properties and visible light response

First-principles calculations based on density functional theory (DFT) were used to study the interfacial properties and its effect on visible light response for the hybrid graphene/anatase TiO2 nanocomposites (G/ATN). There was a notable charge transfer from graphene layer to anatase TiO2 in the ground electronic state, leading to an excess of holes in the graphene layer. After combined with graphene, new visible light absorption bands involving transitions between the C 2p states and other states will appear in the middle of the energy gap of anatase TiO2. Electrons at the top of the valence bands can be directly excited from graphene (C 2p) to the bottom of the conduction band in the anatase TiO2 (Ti 3d) easy. The separation of photoexcited electron-hole pairs was promoted effectively and their recombination was suppressed greatly. The notable visible light response and enhanced photocatalytic activity from our calculations validated the experimental report [Adv. Mater. 2012, 24, 1084-1088]. It indicated that the proposed model and simulated methods for the G/ATN were reasonable and might be applied to design graphene/semiconductor composite photocatalysts, which was conducive to the discovery of new composite functional materials. (C) 2013 Elsevier B.V. All rights reserved.