First-principles calculation of N:H codoping effect on energy gap narrowing of TiO2

Abstract

The energy band structures and density of states for N-doped and N:H-doped anatase TiO 2 are calculated based on the first-principles density-functional theory. For N-doped TiO 2 , there appear two isolated states above the top of the valence band and the band gap narrowing is very small. With the same nitrogen dopant concentration, N:H doping yields a significant band gap narrowing. The calculated results support our experimental data that N:H-doped TiO 2 exhibited higher visible-light photocatalytic efficiency than the N-doped one.

Effect of Electronegativity and Charge Balance on the Visible-Light-Responsive Photocatalytic Activity of Nonmetal Doped Anatase TiO2

“…From Figure 4, we can see clearly that with the decrease of the electronegativity difference between oxygen and substitutional elements, (N, C, and B), the impurity states become closer to the VBM. In addition, when the charges are balanced, the electron donors (H) may contribute to the lowering of the energy levels related to the acceptors (N, C, and B), resulting in the impurity states downward to the VBM, which agrees well with the previous studies [40]. Accordingly, the N : H species may enhance the mixing of impurity states induced by N 2p states and O 2p atomic orbitals in the VBM, and finally new valence bands can be formed, which could contribute to the formation of the band-band transition, in favor of the visible-light-driven catalytic activities.…”

First principles calculations of electronic and optical properties of Mo-doped rutile TiO2

“…Theoretical investigations have also been carried out to study the band structures of TiO 2 phases including anatase [13][14][15] and rutile [16][17][18][19][20]. Mo, as a transition metal, has been used to dope TiO 2 for photocatalytic applications, showing the effects to make the materials catalytically active under visible light [21][22][23][24][25][26].…”

Effect of carbon/hydrogen species incorporation on electronic structure of anatase-TiO2

“…17 Recently, Mi and his co-workers reported that N/Hcodoped TiO 2 shows higher photocatalytic activity than those of both N-doped anatase TiO 2 and pure TiO 2 . 18 Alvaro reported that the photocatalytic activity of TiO 2 can be enhanced by complexation with organic additives. 19 Moreover, Davies et al reported that the C-H bond has a significant effect on photocatalytic activity.…”