基于密度泛函理论, 采用第一性原理赝势平面波方法计算了Co、Cr单掺杂以及Co-Cr共掺杂金红石型TiO2的能带结构、态密度和光学性质. 计算结果表明: 纯金红石的禁带宽度为3.0 eV, Co掺杂金红石型TiO2的带隙为1.21 eV, 导带顶和价带底都位于G点处, 仍为直接带隙, 在价带与导带之间出现了由Co 3d和Ti 3d轨道杂化形成的杂质能级；Cr掺杂金红石型TiO2的直接带隙为0.85 eV, 在价带与导带之间的杂质能级由Cr 3d和Ti 3d轨道杂化轨道构成, 导带和价带都向低能级方向移动；Co-Cr共掺杂, 由于电子的强烈杂化, 使O-2p态和Ti-3d 态向 Co-3d 和 Cr-3d态移动, 使价带顶能级向高能级移动而导带底能级向低能方向移动, 极大地减小了禁带的宽度, 也是共掺杂改性的离子选择依据. 掺杂金红石型TiO2的介电峰、折射率和吸收系数峰都向低能方向移动；在E<2.029 eV的范围内, 纯金红石的ε2、k和吸收系数为零, 掺杂后的跃迁强度都大于未掺杂时的跃迁强度, Co-Cr共掺杂的跃迁强度大于Co掺杂及Cr掺杂, 说明Co、Cr共掺杂更能增强电子在低能端的光学跃迁, 具有更佳的可见光催化性能.

Based on the density functional theory, using the first principles pseudopotential plane wave method to calculate Co, Cr doped and Co, Cr Co doped rutile TiO2 band structure, density of States and optical properties. The results show that: the band gap of pure rutile is 3.00 eV, Co doped rutile TiO2 band gap of 1.21 eV, the conduction band and valence band top bottom are located in the G spot, is a direct band gap between the valence and conduction band, the impurity level by Co 3d and Ti 3d hybridization; Cr doped rutile TiO2 direct band gap of 0.85 eV, the impurity levels between the valence and conduction band by Cr 3d and Ti 3D orbital track structure, the conduction and valence bands are moving toward low level direction, Also, it is doping modification of ion selective basis; Due to the strong hybrid electron, make the O-2p state and the Ti-3d state to the Co-3d state and Cr-3d mobile of Co-Cr Co-doped, the valence band energy shifts to a higher energy level and the bottom of the conduction band energy level shift to lower energy, so greatly reducing the band gap width. The dielectric peak doped rutile TiO2, refractive index and absorption coefficient all shift to lower energy; In the range of E<2.029 eV, pure rutile imaginary part of dielectric function, k and absorption coefficient is zero, the transition strength after doping is higher than the transition intensity of undoped zno, Transition intensity of Co, Cr Co-doped is greater than Co doped and Cr doped, Co, Cr Co-doped can strengthen the electron optical transitions in the low end, visible light catalytic performance has better.