Origin of the Enhanced Visible-Light Absorption in N-Doped Bulk Anatase TiO 2 from First-Principles Calculations
Type
ArticleAuthors
Harb, Moussab
Sautet, P.
Raybaud, P.
KAUST Grant Number
UK-C0017Date
2011-09-13Online Publication Date
2011-09-13Print Publication Date
2011-10-06Permanent link to this record
http://hdl.handle.net/10754/599118
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Extension of the absorption properties of TiO2 photocatalytic materials to the visible part of the solar spectrum is of major importance for energy and cleaning up applications. We carry out a systematic study of the N-doped anatase TiO2 material using spin-polarized density functional theory (DFT) and the range-separated hybrid HSE06 functional. The thermodynamic stability of competitive N-doped TiO2 structural configurations is studied as a function of the oxygen chemical potential and of various chemical doping agents: N2, (N2 + H2), NH3, N2H4. We show that the diamagnetic TiO (2-3x)N2x system corresponding to a separated substitutional N species (with 2-4% N impurities) and formation of one-half concentration of O vacancies (1-2 atom %) is an optimal configuration thermodynamically favored by NH3, N2H4, and (N2 + H2) chemical doping agents presenting a dual nitrating-reducing character. The simulated UV-vis absorption spectra using the perturbation theory (DFPT) approach demonstrates unambiguously that the diamagnetic TiO(2-3x)N2x system exhibits the enhanced optical absorption in N-doped TiO2 under visible-light irradiation. Electronic analysis further reveals a band gap narrowing of 0.6 eV induced by delocalized impurity states located at the top of the valence band of TiO 2. A fruitful comparison with experimental data is furnished. © 2011 American Chemical Society.Citation
Harb M, Sautet P, Raybaud P (2011) Origin of the Enhanced Visible-Light Absorption in N-Doped Bulk Anatase TiO 2 from First-Principles Calculations . The Journal of Physical Chemistry C 115: 19394–19404. Available: http://dx.doi.org/10.1021/jp204059q.Sponsors
This work was supported by Award No. UK-C0017, made by King Abdullah University of Science and Technology (KAUST). The authors thank E. Puzenat (IRCELYON) for fruitful discussion.Publisher
American Chemical Society (ACS)ae974a485f413a2113503eed53cd6c53
10.1021/jp204059q