Polaron-adsorbate coupling at the TiO2(110)-carboxylate interface

Tanner, A. J., Wen, B., Ontaneda, J., Zhang, Y., Grau-Crespo, R. ORCID: https://orcid.org/0000-0001-8845-1719, Fielding, H. H., Selloni, A. and Thornton, G. (2021) Polaron-adsorbate coupling at the TiO2(110)-carboxylate interface. Journal of Physical Chemistry Letters, 12 (14). pp. 3571-3576. ISSN 1948-7185 doi: 10.1021/acs.jpclett.1c00678

Abstract/Summary

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.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/97417
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Uncontrolled Keywords	TiO2, surface science, polarons, DFT
Publisher	American Chemical Society
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