中文摘要：

采用第一性原理计算方法讨论了TiO2（101）、（001）、（010）、（110）和（100）等活性表面的稳定顺序,选取最稳定表面（101）和最活泼表面（001）为研究对象,探讨石墨烯的复合对TiO2表面结构和性能的影响。结果表明：石墨烯的复合改变了TiO2的电子结构和电荷分布,导致电子由TiO2表面迁移到石墨烯。石墨烯/TiO2导带底端主要由Ti 3d组成,其分布向低能级部分移动,带隙大大减小,电子跃迁变得容易,吸收边波长发生红移,拓展了光催化剂的光响应范围,提高了其光催化活性。

英文摘要：

In our work,it was determined that the（101）facet was the most stable surface and（001）facet was the most active surface among all facets of anatase TiO2.Firstprinciples calculations based on density functional theory（DFT）were used to explore the effect of graphene hybridization on the electronic structure and properties of anatase TiO2 with typical facet,such as（101）and（001）.Due to the hybridization of graphene,the charge distributions of atoms between the interface of TiO2 and graphene were modified,which cause the electron migrate from the surface of TiO2 to graphene.The bottom of conduction band was mainly composed of Ti3 d,which migrated to the low energy region.Both the energy gap of graphene/TiO2（001）and energy gap of graphene/TiO2（101）were narrowed,which indicated the electron transit from valence band to conduction band when under low-energy light irradiation.It indicated that the photocatalytic activities of the nanocomposites were enhanced and the optical response ranges were expanded to the long wavelength region.