Synergistic Effects on Band Gap-Narrowing in Titania by Codoping from First-Principles Calculations

The large intrinsic band gap in TiO2 has hindered severely its Potential application for visible-light irradiation. In this study, we have used a passivated approach to modify the band edges of anatase-TiO2 by codoping of X (N, C) with transition metals (TM = W, Re, Os.) to extend the absorption edge to longer visible-light wavelengths. It was found that all the codoped systems can narrow the band gap significantly; in particular (N+W)-codoped systems could serve as remarkably better photocatalysts with both narrowing of the band gap and relatively smaller formation energies and larger binding energies than those of (C+TM) and (N+TM)-codoped systems Our theoretical calculations provide meaningful guides for experiments to develop more powerful visible-light photocatalysts