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Adsorption of L-cysteine on rutile TiO2(110)

Författare:
Publiceringsår: 2011
Språk: Engelska
Sidor: 179-186
Publikation/Tidskrift/Serie: Surface Science
Volym: 605
Nummer: 1-2
Dokumenttyp: Artikel
Förlag: Elsevier Science BV

Sammanfattning

We have used X-ray photoelectron spectroscopy to study the adsorption of L-cysteine on a rutile TiO2(110) surface at room temperature and -65 degrees C. For the molecules in direct contact with the surface our results suggest that the molecules bind dissociatively to the fivefold-coordinated Ti atoms of the surface through their deprotonated carboxylic groups. A second, dissociative interaction occurs between the molecular thiol groups and the surface. It is attributed to a dissociative bond to the bridging oxygen vacancies. Most likely, the thiol groups are deprotonated and a bond is formed between the thiolates and defects. In an alternative scenario, the C-S bond is cleaved and atomic sulfur binds to the defects. With regard to the molecular amino groups, they remain neutral at the lowest investigated coverages (0.3-0.5 ML), but already starting from around 0.7 ML nominal coverage protons are being transferred to them. The fraction of protonated amino groups increases with coverage and becomes dominating in multilayers prepared at room temperature and -65 degrees C. In these multilayers the carboxylic groups are deprotonated. (C) 2010 Elsevier B.V. All tights reserved.

Disputation

Nyckelord

  • Physics and Astronomy
  • L-cysteine
  • X-ray photoelectron spectroscopy
  • Rutile TiO2(110)
  • Amino
  • acid
  • Adsorption

Övrigt

Published
Yes
  • ISSN: 0039-6028

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