The First Principle On Metal Doped Anatase TiO₂ Photocatalyst

The CASTEP of Materials Studio 4.3, developed by Accelrys, was used to calculated. Firstly, the structure of pure and doped anatase TiO₂ was optimized. Secondly, their electronic structure, formation energy, charge density, optical property and so on were analysed in great detail. The computational and analytical results were as following:(1) The four kinds supcells of C doping anatase TiO₂ were calculated, that is C&O, C^2-&O, C&Ti and C⁴⁺&Ti. Their supercell structure, band structure, state of density, and optical absorption property were studied by DFT. We were going to make the doping effect of defferent doping style more clear.(2) The doped TiO₂ with 3d transition metal was discussed in details, and a Ti was replaceed with a metal atom. we have got nine kinds of doped TiO₂, Sc-TiO₂, V-TiO₂, Cr-TiO₂, Mn-TiO₂, Fe-TiO₂, Co-TiO₂, Ni-TiO₂, Cu-TiO₂ and Zn-TiO₂. The results show that the local impurity level was mostly 3d orbital of doping atom, and whether the absorption wave was red shift or not was controled by the position of impurity band.(3) 4d transition metal was Y,Zr,Nb,Mo,Ru,Rh,Pd,Ag and Cd. The defect formation energies, the band structures and the density of states were calculated to analyze the energetic properties and electronic structures of 4d doped TiO₂. The doped TiO₂ was classified four parts by their characteristic impurity band.(4) First-principles density functional theory calculations were performed on the electronic properties of rare earth metal-doped anatase TiO₂, where Ti was replaced by 17 kinds of rare earth metals, to explore the effect of the dopants on the band edges and their absorption spectra. Seventeen kinds of metals doped TiO₂ are classified three parts according to their band structures and location of impurity states.(5) For Cu-TiO₂, Ag-TiO₂, Au-TiO₂, Zn-TiO₂, Cd-TiO₂ and Hg-TiO₂, their absorption wave was red shift and the absorption coefficient is also enhanced.