Enhanced optical absorption and photocatalytic activity of anatase TiO2 through C-Nd-codoped: A DFT plus U calculations

The electronic and optical properties are investigated using density functional theory plus U approach in C-Nd monodoped and codoped anatase TiO2. The calculated results indicate that C dopant can enhance the intensity of optical absorption and Nd dopant can extend the optical absorption range into the whole visible spectrum in C-Nd-codoped anatase TiO2, and the Nd 4f states can effectively reduce the recombination of photo-excited electron-hole pairs thus achieving higher visible light photocatalytic activity for hydrogen production by water splitting than pure TiO2. Moreover, we also study the effects of doping concentration and impurity distance in C-Nd-codoped anatase TiO2 system, finding that the higher doping concentration, the stronger absorption activity, and absorption activity increases with the shortness of impurity distance due to the assemblage of impurity states.