The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces

G. J. Fleming, K. Adib, J. A. Rodriguez, M. A. Barteau, J. M. White, Hicham Idriss

Research output: Contribution to journalArticle

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Abstract

The reaction of the amino acid DL-proline is studied over stoichiometric and Ar-ions sputtered (reduced) TiO2(110) single crystal surfaces by synchrotron High Resolution X-ray Photorelectron Spectroscopy (HRXPS). On the stoichiometric surface proline gives two different species at 300 K: dissociated and zwitterionic. Upon heating the zwitterionic structure is removed first from the surface followed by the dissociated form. The C1s signal for the COO function is found close to 288.5 eV for both forms while the N1s for the dissociated form is found at 400.0 eV and that of the zwitterionic from close to 401.8 eV. From the attenuation of the Ti2p signal the surface coverage was estimated less than 1/2 (about 0.35). This smaller coverage than dissociatively adsorbed carboxylic acids on this surface (usually close to 1/2), is attributed to lateral repulsion caused by the ring of adjacent proline molecules adsorbed on five-fold coordinated Ti cations along the [001] direction. On the reduced surface the amount of zwitterion structure is found two times higher than that on the stoichiometric surface, at 300 K, most likely due to the considerable decrease of the amount of surface oxygen available. The stability of the zwitterionic structure on this surface is however found similar to that found on the stoichiometric surface. In addition, evidence of oxidation of reduced Ti cations upon adsorption at 300 K is noticed and explained as breaking of the carbon-oxygen bond of a fraction of adsorbed proline. Variable temperature HRXPS has been collected and results indicated that proline is more stable on the reduced surface compared to the stoichiometric surface. (C) 2008 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)2029-2038
Number of pages10
JournalSurface Science Reports
Volume602
Issue number12
Early online date22 Apr 2008
DOIs
Publication statusPublished - 15 Jun 2008

Keywords

  • TiO2(110) single crystal
  • proline
  • XPS
  • binding energy
  • zwitterion
  • single-crystal surfaces
  • temperature-programmed desorption
  • gas-phase
  • photoelectron-spectroscopy
  • infrared-spectroscopy
  • formic-acid
  • glycine adsorption
  • L-Alanine
  • TIO2(110)
  • CU(110)

Cite this

Fleming, G. J., Adib, K., Rodriguez, J. A., Barteau, M. A., White, J. M., & Idriss, H. (2008). The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces. Surface Science Reports, 602(12), 2029-2038. https://doi.org/10.1016/j.susc.2008.04.010

The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces. / Fleming, G. J.; Adib, K.; Rodriguez, J. A.; Barteau, M. A.; White, J. M.; Idriss, Hicham.

In: Surface Science Reports, Vol. 602, No. 12, 15.06.2008, p. 2029-2038.

Research output: Contribution to journalArticle

Fleming, GJ, Adib, K, Rodriguez, JA, Barteau, MA, White, JM & Idriss, H 2008, 'The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces', Surface Science Reports, vol. 602, no. 12, pp. 2029-2038. https://doi.org/10.1016/j.susc.2008.04.010
Fleming GJ, Adib K, Rodriguez JA, Barteau MA, White JM, Idriss H. The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces. Surface Science Reports. 2008 Jun 15;602(12):2029-2038. https://doi.org/10.1016/j.susc.2008.04.010
Fleming, G. J. ; Adib, K. ; Rodriguez, J. A. ; Barteau, M. A. ; White, J. M. ; Idriss, Hicham. / The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces. In: Surface Science Reports. 2008 ; Vol. 602, No. 12. pp. 2029-2038.
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abstract = "The reaction of the amino acid DL-proline is studied over stoichiometric and Ar-ions sputtered (reduced) TiO2(110) single crystal surfaces by synchrotron High Resolution X-ray Photorelectron Spectroscopy (HRXPS). On the stoichiometric surface proline gives two different species at 300 K: dissociated and zwitterionic. Upon heating the zwitterionic structure is removed first from the surface followed by the dissociated form. The C1s signal for the COO function is found close to 288.5 eV for both forms while the N1s for the dissociated form is found at 400.0 eV and that of the zwitterionic from close to 401.8 eV. From the attenuation of the Ti2p signal the surface coverage was estimated less than 1/2 (about 0.35). This smaller coverage than dissociatively adsorbed carboxylic acids on this surface (usually close to 1/2), is attributed to lateral repulsion caused by the ring of adjacent proline molecules adsorbed on five-fold coordinated Ti cations along the [001] direction. On the reduced surface the amount of zwitterion structure is found two times higher than that on the stoichiometric surface, at 300 K, most likely due to the considerable decrease of the amount of surface oxygen available. The stability of the zwitterionic structure on this surface is however found similar to that found on the stoichiometric surface. In addition, evidence of oxidation of reduced Ti cations upon adsorption at 300 K is noticed and explained as breaking of the carbon-oxygen bond of a fraction of adsorbed proline. Variable temperature HRXPS has been collected and results indicated that proline is more stable on the reduced surface compared to the stoichiometric surface. (C) 2008 Elsevier B.V. All rights reserved.",
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T1 - The adsorption and reactions of the amino acid proline on rutile TiO2(010) surfaces

AU - Fleming, G. J.

AU - Adib, K.

AU - Rodriguez, J. A.

AU - Barteau, M. A.

AU - White, J. M.

AU - Idriss, Hicham

PY - 2008/6/15

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N2 - The reaction of the amino acid DL-proline is studied over stoichiometric and Ar-ions sputtered (reduced) TiO2(110) single crystal surfaces by synchrotron High Resolution X-ray Photorelectron Spectroscopy (HRXPS). On the stoichiometric surface proline gives two different species at 300 K: dissociated and zwitterionic. Upon heating the zwitterionic structure is removed first from the surface followed by the dissociated form. The C1s signal for the COO function is found close to 288.5 eV for both forms while the N1s for the dissociated form is found at 400.0 eV and that of the zwitterionic from close to 401.8 eV. From the attenuation of the Ti2p signal the surface coverage was estimated less than 1/2 (about 0.35). This smaller coverage than dissociatively adsorbed carboxylic acids on this surface (usually close to 1/2), is attributed to lateral repulsion caused by the ring of adjacent proline molecules adsorbed on five-fold coordinated Ti cations along the [001] direction. On the reduced surface the amount of zwitterion structure is found two times higher than that on the stoichiometric surface, at 300 K, most likely due to the considerable decrease of the amount of surface oxygen available. The stability of the zwitterionic structure on this surface is however found similar to that found on the stoichiometric surface. In addition, evidence of oxidation of reduced Ti cations upon adsorption at 300 K is noticed and explained as breaking of the carbon-oxygen bond of a fraction of adsorbed proline. Variable temperature HRXPS has been collected and results indicated that proline is more stable on the reduced surface compared to the stoichiometric surface. (C) 2008 Elsevier B.V. All rights reserved.

AB - The reaction of the amino acid DL-proline is studied over stoichiometric and Ar-ions sputtered (reduced) TiO2(110) single crystal surfaces by synchrotron High Resolution X-ray Photorelectron Spectroscopy (HRXPS). On the stoichiometric surface proline gives two different species at 300 K: dissociated and zwitterionic. Upon heating the zwitterionic structure is removed first from the surface followed by the dissociated form. The C1s signal for the COO function is found close to 288.5 eV for both forms while the N1s for the dissociated form is found at 400.0 eV and that of the zwitterionic from close to 401.8 eV. From the attenuation of the Ti2p signal the surface coverage was estimated less than 1/2 (about 0.35). This smaller coverage than dissociatively adsorbed carboxylic acids on this surface (usually close to 1/2), is attributed to lateral repulsion caused by the ring of adjacent proline molecules adsorbed on five-fold coordinated Ti cations along the [001] direction. On the reduced surface the amount of zwitterion structure is found two times higher than that on the stoichiometric surface, at 300 K, most likely due to the considerable decrease of the amount of surface oxygen available. The stability of the zwitterionic structure on this surface is however found similar to that found on the stoichiometric surface. In addition, evidence of oxidation of reduced Ti cations upon adsorption at 300 K is noticed and explained as breaking of the carbon-oxygen bond of a fraction of adsorbed proline. Variable temperature HRXPS has been collected and results indicated that proline is more stable on the reduced surface compared to the stoichiometric surface. (C) 2008 Elsevier B.V. All rights reserved.

KW - TiO2(110) single crystal

KW - proline

KW - XPS

KW - binding energy

KW - zwitterion

KW - single-crystal surfaces

KW - temperature-programmed desorption

KW - gas-phase

KW - photoelectron-spectroscopy

KW - infrared-spectroscopy

KW - formic-acid

KW - glycine adsorption

KW - L-Alanine

KW - TIO2(110)

KW - CU(110)

U2 - 10.1016/j.susc.2008.04.010

DO - 10.1016/j.susc.2008.04.010

M3 - Article

VL - 602

SP - 2029

EP - 2038

JO - Surface Science Reports

JF - Surface Science Reports

SN - 0167-5729

IS - 12

ER -