New insights into the origin of visible-light photocatalytic activity in Se-modified anatase TiO2 from screened coulomb hybrid DFT calculations

Handle URI:
http://hdl.handle.net/10754/563144
Title:
New insights into the origin of visible-light photocatalytic activity in Se-modified anatase TiO2 from screened coulomb hybrid DFT calculations
Authors:
Harb, Moussab ( 0000-0001-5540-9792 )
Abstract:
We report a systematic study on the optoelectronic properties of Se-modified anatase TiO2 investigated by DFT (including the perturbation theory approach DFPT) within the screened coulomb hybrid HSE06 formalism to guarantee accurate band gap and electronic excitation predictions. Various selenium species at substitutional sites for O or Ti, at interstitial sites, as well as at mixed substitutional/interstitial sites are studied. Among the explored structures, Ti(1-2x)O2Se2x (containing Se4+ species), TiO(2-x)Sex (containing Se2- species), and TiO(2-x)Se2x (containing Se2 2- species) reveal significant enhanced visible-light optical absorption spectra with new absorption features appearing at 500, 600, and 690 nm, respectively. Our calculated spectra are found to be in good agreement with those obtained in available experimental works. The band gap narrowing in these materials originates from incorporation of newly occupied electronic levels within 0.5-1.5 eV above the original valence band of TiO 2, leading to new narrowed band gaps of 2.5, 2.0, and 1.8 eV respectively. Our calculations also reveal suitable band positions of Ti (1-2x)O2Se2x and TiO(2-x)Se x for overall water splitting, whereas TiO(2-x)Se 2x shows an unsuitable valence band position for the oxygen evolution reaction. In contrast, the localized electronic character of the new occupied states on the Se 4p orbitals and only on the O 2p orbitals linked to the Se species makes the holes mobility limited in this material and the recombination rate of charge carriers greatly increased in the bulk. © 2013 American Chemical Society.
KAUST Department:
KAUST Catalysis Center (KCC)
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry C
Issue Date:
5-Dec-2013
DOI:
10.1021/jp406714e
Type:
Article
ISSN:
19327447
Appears in Collections:
Articles; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorHarb, Moussaben
dc.date.accessioned2015-08-03T11:36:49Zen
dc.date.available2015-08-03T11:36:49Zen
dc.date.issued2013-12-05en
dc.identifier.issn19327447en
dc.identifier.doi10.1021/jp406714een
dc.identifier.urihttp://hdl.handle.net/10754/563144en
dc.description.abstractWe report a systematic study on the optoelectronic properties of Se-modified anatase TiO2 investigated by DFT (including the perturbation theory approach DFPT) within the screened coulomb hybrid HSE06 formalism to guarantee accurate band gap and electronic excitation predictions. Various selenium species at substitutional sites for O or Ti, at interstitial sites, as well as at mixed substitutional/interstitial sites are studied. Among the explored structures, Ti(1-2x)O2Se2x (containing Se4+ species), TiO(2-x)Sex (containing Se2- species), and TiO(2-x)Se2x (containing Se2 2- species) reveal significant enhanced visible-light optical absorption spectra with new absorption features appearing at 500, 600, and 690 nm, respectively. Our calculated spectra are found to be in good agreement with those obtained in available experimental works. The band gap narrowing in these materials originates from incorporation of newly occupied electronic levels within 0.5-1.5 eV above the original valence band of TiO 2, leading to new narrowed band gaps of 2.5, 2.0, and 1.8 eV respectively. Our calculations also reveal suitable band positions of Ti (1-2x)O2Se2x and TiO(2-x)Se x for overall water splitting, whereas TiO(2-x)Se 2x shows an unsuitable valence band position for the oxygen evolution reaction. In contrast, the localized electronic character of the new occupied states on the Se 4p orbitals and only on the O 2p orbitals linked to the Se species makes the holes mobility limited in this material and the recombination rate of charge carriers greatly increased in the bulk. © 2013 American Chemical Society.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleNew insights into the origin of visible-light photocatalytic activity in Se-modified anatase TiO2 from screened coulomb hybrid DFT calculationsen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalThe Journal of Physical Chemistry Cen
kaust.authorHarb, Moussaben
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