Effect of N and Fe codoping on the electronic structure and optical properties of TiO2 from first-principles study

The electronic structure and optical properties of N and Fe codoping TiO2 have been investigated by first-principles calculations based on density functional theory. The calculated results indicate that the stability of N and Fe codoping TiO2 will change at different substitutional sites of N and Fe. The mechanism of band gap narrowing of doping TiO2 is discussed by investigating the density of state. The different substitutional site of N and Fe in codoping TiO2 influences the visible-light absorption. An increased visible-light absorption for doping TiO2 results from the synergistic effect of N and Fe codoping. Therefore, N and Fe codoping may enhance the visible-light photocatalytic activity of TiO2.