In this paper, first-principle calculations based on density functional theory were carried out to explore the interface properties of the hybrid graphene/anatase TiO 2 (001) nanocomposites (G/AT(001)N). The effect of graphene hybridization on energy gap, surface chemical bonding, interfacial charge transfer, and visible light response was investigated in detail. Because of the hybridization of graphene, the band structure of the G/AT(001)N was modified, and the energy gap was reduced to 0.47 eV. Electrons in the bottom of the valence band (VB) of anatase TiO 2 could disperse to the upper part of the VB. And electrons in the upper part of the VB of anatase TiO 2 were likely to be directly excited to graphene under visible light irradiation, which promoted the formation of wellseparated electron−hole pairs. The interfacial electron transfer in the ground electronic state promoted electrons increased on graphene and substantial holes accumulated in TiO 2 (001) facet. Good linkage between TiO 2 (001) facet and graphene could facilitate the charge transfer, promoting photocatalytic efficiency improvement. Hybridization of graphene brought an obvious red shift in the absorption edge and enhanced absorption intensity in the visible region, which indicated the enhancement of photocatalytic performance. The calculation results illustrated the reported experimental observation [J. Phys. Chem. Lett. 2011, 2, 894−899] and would provide new insights into the design of graphene-based semiconductor photocatalysts.

The layered structural model was proposed to study the geometry and electronic properties of the ( WO 3)x/( TiO 2)y heterostructures in this paper. The geometry and electronic properties were affected greatly by the relative proportion of TiO 2 and WO 3 in the nanocomposites. The minimum band gap of ( WO 3)x/( TiO 2)y heterostructures decreased with the proportion of WO 3 increasing but increased with the proportion of TiO 2 increasing. Interestingly, electrons at the upper valence band (VB) can be directly excited from 2p and 3d orbitals of titania to the conduction band (CB), which was mainly consisted of 5d orbitals of tungsten trioxide. The effective electron mass of ( WO 3)x/( TiO 2)y heterostructures was higher than that of pure TiO 2. It indicated that the electron–hole recombination rate of hybrid ( WO 3)x/( TiO 2)y heterostructure was lower than that of pure TiO 2, which might imply that photocatalytic activities of the hybrid ( WO 3)x/( TiO 2)y heterostructures were enhanced under visible light irradiation. The theoretical results might offer a new useful guide for designing semiconductors photocatalyst, such as heterostructure nanocomposites.