Explaining the enhanced photocatalytic activity of Degussa P25 mixed-phase TiO2 using EPR

Deanna C. Hurum, Alexander G. Agrios, Kimberly A Gray*, Tijana Rajh, Marion C. Thurnauer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1567 Scopus citations

Abstract

Charge separation characteristics of a high-activity, mixed-phase titania photocatalyst (Degussa P25) are probed by EPR spectroscopy. While previous proposals consider rutile as a passive electron sink hindering recombination in anatase, this research details the critical and active role of rutile in TiO2 formulations. The inactivity of pure-phase rutile is due in part to rapid rates of recombination. Yet, in mixed-phase TiO2, charges produced on rutile by visible light are stabilized through electron transfer to lower energy anatase lattice trapping sites. These results suggest that within mixed-phase titania (P25) there is a morphology of nanoclusters containing atypically small rutile crystallites interwoven with anatase crystallites. The transition points between these two phases allow for rapid electron transfer from rutile to anatase. Thus, rutile acts as an antenna to extend the photoactivity into visible wavelengths and the structural arrangement of the similarly sized TiO2 crystallites creates catalytic "hot spots" at the rutile-anatase interface.

Original languageEnglish (US)
Pages (from-to)4545-4549
Number of pages5
JournalJournal of Physical Chemistry B
Volume107
Issue number19
StatePublished - May 15 2003

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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