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Synergistic effects of Bi/S codoping on visible light-activated anatase TiO2 photocatalysts from first principles
Long, Run; English, Niall J.
The electronic properties and photocatalytic activity of S and/or Bi-doped anatase TiO2 are investigated by first-principles density functional theory calculations. For S-doped TiO2, S 3p states locate above the top of the valence band and mix with O 2p states, leading to band gap narrowing. For Bi-doped anatase, the energy levels of the impurity Bi 6s states lie below the bottom of the conduction band while the Fermi level EF lies above the gap states, indicating the gap states are fully occupied. The transition from Bi 6s to Ti 3d states is responsible for a red-shift of the visible light absorption edge. In Bi/S–doped TiO2, both S 3p acceptor states and partially occupied Bi 6s donor states hybridized with S 3p appear simultaneously; this observation suggests that photocatalytic efficiency would be improved significantly due to greater separation of electron-hole pairs. These findings present a reasonable explanation of recent experimental results. Science Foundation Ireland Irish Research Council for Science, Engineering and Technology Other funder Irish Centre for High End Computing (ICHEC)
Keyword(s): Synergistic effect; Electronic structure; Co-doping; TiO2; Titanium dioxide; Doped semiconductors; Density functionals
Publication Date:
2011
Type: Journal article
Peer-Reviewed: Unknown
Language(s): English
Institution: University College Dublin
Publisher(s): ACS Publications
File Format(s): other; application/pdf
First Indexed: 2012-08-25 05:18:54 Last Updated: 2018-10-11 15:30:54