Generation of organic radicals during photocatalytic reactions on TiO 2

M. A. Henderson, N. A. Deskins, R. T. Zehr, Michel Dupuis

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Using a variety of organic carbonyl molecules (R1C(O)R 2) and the rutile TiO2(1 1 0) surface as a model photocatalyst, we demonstrate both experimentally and theoretically that ejection of organic radicals from TiO2 surfaces is likely a prevalent reaction process occurring during heterogeneous photooxidation of organic molecules. Organic carbonyls react with coadsorbed oxygen species to form organic diolates which are more strongly bound to TiO2 than are the parent carbonyls. The parent carbonyls, when bound to TiO2(1 1 0) in an ν1 configuration, are photo-inactive toward valence band holes. However, the diolates are shown to photodecompose by ejection of one of the two R substituents from the surface into the gas phase, leaving behind the carboxylate of the other R group. Theoretical calculations using DFT show that in most cases the choice of which R group is ejected can be predicted based on the C-R bond energies and, to a lesser extent, the stability of the ejected R group.

Original languageEnglish
Pages (from-to)205-212
Number of pages8
JournalJournal of Catalysis
Volume279
Issue number1
DOIs
Publication statusPublished - Apr 1 2011

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ejection
Molecules
Photooxidation
photooxidation
Photocatalysts
Valence bands
Discrete Fourier transforms
rutile
carboxylates
molecules
Gases
vapor phases
Oxygen
valence
oxygen
configurations
energy
titanium dioxide

Keywords

  • DFT
  • Photocatalysis
  • Photodesorption
  • Radicals
  • Surface
  • Theory
  • TiO

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

Cite this

Generation of organic radicals during photocatalytic reactions on TiO 2 . / Henderson, M. A.; Deskins, N. A.; Zehr, R. T.; Dupuis, Michel.

In: Journal of Catalysis, Vol. 279, No. 1, 01.04.2011, p. 205-212.

Research output: Contribution to journalArticle

Henderson, M. A. ; Deskins, N. A. ; Zehr, R. T. ; Dupuis, Michel. / Generation of organic radicals during photocatalytic reactions on TiO 2 . In: Journal of Catalysis. 2011 ; Vol. 279, No. 1. pp. 205-212.
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