New Insights into the Band-Gap Narrowing of (N, P)-Codoped TiO2 from Hybrid Density Functional Theory Calculations

Authors

  • Run Long,

    Corresponding author
    1. The SEC Strategic Research Cluster and the Centre for Synthesis and Chemical Biology, School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4 (Ireland), Fax: (+353) 1-716-1177
    • The SEC Strategic Research Cluster and the Centre for Synthesis and Chemical Biology, School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4 (Ireland), Fax: (+353) 1-716-1177
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  • Niall J. English

    Corresponding author
    1. The SEC Strategic Research Cluster and the Centre for Synthesis and Chemical Biology, School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4 (Ireland), Fax: (+353) 1-716-1177
    • The SEC Strategic Research Cluster and the Centre for Synthesis and Chemical Biology, School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4 (Ireland), Fax: (+353) 1-716-1177
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Abstract

The electronic properties of anatase-TiO2 codoped by N and P at different concentrations have been investigated via generalized Kohn–Sham theory with the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional for exchange-correlation in the context of density functional theory. At high doping concentrations, we find that the high photocatalytic activity of (N, P)-codoped anatase TiO2 vis-à-vis the N-monodoped case can be rationalized by a double-hole-mediated coupling mechanism [Yin et al., Phys. Rev. Lett.2011,106, 066801] via the formation of an effective N[BOND]P bond. On the other hand, Ti3+ and Ti4+ ions’ spin double-exchange results in more substantial gap narrowing for larger separations between N and P atoms. At low doping concentrations, double-hole-coupling is dominant, regardless of the N[BOND]P distance.

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