Complex and charge transfer between TiO2 and pyrroloquinoline quinone

Nada M. Dimitrijevic, Oleg G. Poluektov, Zoran V. Saponjic, Tijana Rajh

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Pyrroloquinoline quinone (PQQ) forms a tridentate complex with coordinatively unsaturated titanium atoms on the surface of ∼4.5 nm TiO 2 particles; an association constant of K = 550 M-1 per Ti(IV)surf has been determined. Low-temperature electron paramagnetic resonance was employed in identification of localized charges and consequently produced radicals and in determination of charge-transfer processes. The photoexcitation of the PQQ - TiO2 complex results in the transfer of conduction band electrons from TiO2 to bound PQQ and the formation of the semiquinone radical. Attaching dopamine (DA) as an efectron donor and PQQ as an electron acceptor on the surface of TiO2 results in spatial separation of photogenerated charges; the holes localize on dopamine and electrons on PQQ, with higher yields than for each component separately. In this triad-type assembly (PQQ-TiO2/DA) the PQQ that is bound to the particles acts as a sink for electrons allowing their almost complete scavenging even at temperature as low as 4 K.

Original languageEnglish (US)
Pages (from-to)25392-25398
Number of pages7
JournalJournal of Physical Chemistry B
Volume110
Issue number50
DOIs
StatePublished - Dec 21 2006
Externally publishedYes

ASJC Scopus subject areas

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

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