Effects of Nonmetal Doping on Electronic Structures and Optical Property of Anatase TiO2 from First-Principles Calculations

Abstract

Abstract The crystal structures, electronic structures and optical properties of pure and nonmetal (B, C, N, F, P, S and Cl) doping anatase TiO 2 were calculated by the first-principles based on the density functional theory with the plane-wave ultrasoft pesudopotentials method. The calculated results show that the octahedral dipole moments of TiO 2 are increased by nonmetal doping owing to the changes of lattice parameters, bond length and charges on atoms, which is very effective for the separation of photoexcited electron-hole pairs. Because the impurity energy levels are formed by hybridizing with dopants' p states, O 2p states and Ti 3d states, most dopants could narrow the band gap, resulting in its fundamental absorption edge red-shift to visible-light region. According to the calculated results, the effects of nonmetal doping on electronic structure and optical properties of anatase TiO 2 were analyzed and compared, and the roles of nonmetal atoms in TiO 2 photocatalyst under visible-light irradiation were clarified. The calculated results could explain the reasons that some nonmetal-doped TiO 2 have higher photocatalytic activity under visible-light irradiation.