Band gap calculation and photo catalytic activity of rare earths doped rutile TiO 2

Abstract

The density of states (DOS) of 17 kinds of rare earths (RE) doped rutile TiO 2 was by using first-principles density functional theory (DFT) calculation. The band gap widths of RE doped rutile TiO 2 were important factors for altering their absorbing wavelengths. The results show that RE ions could obviously reduce the band gap widths and form of energy of rutile TiO 2 except Lu, Y, Yb and Sc, and the order of absorbing wavelengths of RE doped rutile TiO 2 were the same as that of the results of calculation. The ratio of RE dopant was another important factor for the photo catalytic activity of RE doped rutile TiO 2, and there was an optimal ratio of dopant. There was a constant for predigesting the calculation difficulty, respectively, which were 0.5mol.% and 100 mol −1 under supposition. The band gap widths of RE doped rutile TiO 2 by DFT calculation were much larger than that by experiment. Finally, by transferring the calculation values to experiment values, it could be found and predicted that RE enlarged obviously the absorbing wavelengh of rutile TiO 2. In addition, the degree of RE ions edging out the Ti atom using the parameters of RE elements was computed.