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Electron Traps and the Stark Effect on Hydroxylated Titania Photocatalysts

Szczepankiewicz, Steven H. and Moss, John A. and Hoffmann, Michael R. (2002) Electron Traps and the Stark Effect on Hydroxylated Titania Photocatalysts. Journal of Physical Chemistry B, 106 (31). pp. 7654-7658. ISSN 1520-6106. https://resolver.caltech.edu/CaltechAUTHORS:20150806-153837908

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Abstract

Electric fields generated by photoexcited charge carriers in TiO_2 (anatase) produce Stark effect intensity and wavelength shifts for surface TiO−H stretching vibrations. Deep electron-trapping states affect a single type of TiO−H stretch (Ti(IV)O−H at 3647 cm^(-1) ⇒ Ti(III)O−H at 3716 cm^(-1)). Shallow electron-trapping states, observed as broad absorption bands above 3000 cm^(-1), produce an apparently homogeneous electric field. Intensity changes and corresponding wavelength shifts for ν(TiO−H) are proportional to the magnitude and polarity of the electric field. O_2 is shown to reversibly abstract electrons from shallow trapping states. The results suggest that shallow electron traps are not associated with localized structures, but rather are delocalized across the TiO_2 surface. This behavior may explain the photon-dependent wettability of TiO_2 surfaces.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp020472vDOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp020472vPublisherArticle
ORCID:
AuthorORCID
Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 2002 American Chemical Society. Received: February 20, 2002; In Final Form: May 20, 2002. Publication Date (Web): July 16, 2002. This work was funded by NSF (Grant # BES-9619885 and by DARPA through the Northrop-Grumman Corp.
Funders:
Funding AgencyGrant Number
NSFBES-9619885
Defense Advanced Research Projects Agency (DARPA)UNSPECIFIED
Northrop-Grumman CorporationUNSPECIFIED
Issue or Number:31
Record Number:CaltechAUTHORS:20150806-153837908
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150806-153837908
Official Citation:Electron Traps and the Stark Effect on Hydroxylated Titania Photocatalysts Steven H. Szczepankiewicz, John A. Moss, and Michael R. Hoffmann The Journal of Physical Chemistry B 2002 106 (31), 7654-7658 DOI: 10.1021/jp020472v
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59276
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:07 Aug 2015 19:06
Last Modified:03 Mar 2020 13:01

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