Polaron-Adsorbate Coupling at the TiO2(110)-Carboxylate Interface

Alex J. Tanner, Bo Wen, Jorge Ontaneda, Yu Zhang, Ricardo Grau-Crespo, Helen H. Fielding, Annabella Selloni, Geoff Thornton

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Understanding how adsorbates influence polaron behavior is of fundamental importance in describing the catalytic properties of TiO2. Carboxylic acids adsorb readily at TiO2 surfaces, yet their influence on polaronic states is unknown. Using UV photoemission spectroscopy (UPS), two-photon photoemission spectroscopy (2PPE), and density functional theory (DFT) we show that dissociative adsorption of formic and acetic acids has profound, yet different, effects on the surface density, crystal field, and photoexcitation of polarons in rutile TiO2(110). We also show that these variations are governed by the contrasting electrostatic properties of the acids, which impacts the extent of polaron-adsorbate coupling. The density of polarons in the surface region increases more in formate-terminated TiO2(110) relative to acetate. Consequently, increased coupling gives rise to new photoexcitation channels via states 3.83 eV above the Fermi level. The onset of this process is 3.45 eV, likely adding to the catalytic photoyield.

Original languageEnglish (US)
Pages (from-to)3571-3576
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number14
StatePublished - Apr 15 2021

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physical and Theoretical Chemistry


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