Electronic and optical performances of Si and Fe-codoped TiO2 nanoparticles: A photocatalyst for the degradation of methylene blue

Abstract

The effect of substitutional Si, Fe, and Si and Fe (co)doping on the electronic structure and optical properties of anatase and rutile TiO2 have been investigated by the density functional theory. The calculated results indicate that Si doping TiO2 will induce an obvious band gap narrowing by mixing O 2p with Si 3p states, and a series of impurity energy levels (Fe 3d) appear in edge of the VB and the CB through Fe doping. The synergistic effects of Si and Fe codoping can extend optical absorption edge, which leads to higher visible-light photocatalytic activities than pure and monodoped anatase TiO2. Si and Fe-codoped TiO2 nanoparticles was prepared by a sol-gel-solvothermal method, and the photocatalytic activity of TiO2 nanoparticles was examined by measuring the rate of methylene blue decomposition. The experimental results show that Si and Fe-codoped TiO2 sample exhibits better optical absorption performance and higher photocatalytic activities for the degradation of methylene blue than pure and monodoped TiO2, which verifies the reliability of our calculated results. (c) 2013 Elsevier B.V. All rights reserved.