Characterisation of the oxygen adsorption states on clean and oxidized Ir(110) surfaces

Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review

Autoren

  • S. Ladas
  • S. Kennou
  • N. Hartmann
  • R. Imbihl

Organisationseinheiten

Externe Organisationen

  • University of Patras
  • University of Ioannina
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Details

OriginalspracheEnglisch
Seiten (von - bis)49-56
Seitenumfang8
FachzeitschriftSurface science
Jahrgang382
Ausgabenummer1-3
PublikationsstatusVeröffentlicht - 20 Juni 1997

Abstract

The adsorption of O2 and the reaction of CO with O2 have been investigated on a clean as well as on two differently oxidized Ir(110) surfaces in the pressure range 10-6-10-1 mbar. X-ray photoelectron spectroscopy (XPS), work-function (WF) measurements via a Kelvin probe, LEED and rate measurements were employed as experimental methods. Oxygen adsorption causes a total WF change up to 1.2 eV on the clean surface and up to 1.6 eV on the weakly oxidized surface using the clean surface as a reference level in both cases. On the strongly oxidized surface, the maximum WF change due to chemisorbed oxygen is about 1.8 eV with respect to the WF level of the oxidized surface. XPS measurements of the strongly oxidized, oxygen-saturated surface show two oxygen states characterized by O 1s binding energies of 530.6 and 528.9 eV, with the first state corresponding to the oxide species and chemisorbed oxygen while the second state correlates with the chemisorbed state which is responsible for the large WF increase. Rate measurements during catalytic CO oxidation, which were conducted by varying pCO and pO2 and keeping T fixed, showed the usual clockwise rate hysteresis up to 10-1 mbar with no indication of oscillatory behavior.

ASJC Scopus Sachgebiete

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Characterisation of the oxygen adsorption states on clean and oxidized Ir(110) surfaces. / Ladas, S.; Kennou, S.; Hartmann, N. et al.
in: Surface science, Jahrgang 382, Nr. 1-3, 20.06.1997, S. 49-56.

Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review

Ladas S, Kennou S, Hartmann N, Imbihl R. Characterisation of the oxygen adsorption states on clean and oxidized Ir(110) surfaces. Surface science. 1997 Jun 20;382(1-3):49-56. doi: 10.1016/S0039-6028(97)00095-2
Ladas, S. ; Kennou, S. ; Hartmann, N. et al. / Characterisation of the oxygen adsorption states on clean and oxidized Ir(110) surfaces. in: Surface science. 1997 ; Jahrgang 382, Nr. 1-3. S. 49-56.
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abstract = "The adsorption of O2 and the reaction of CO with O2 have been investigated on a clean as well as on two differently oxidized Ir(110) surfaces in the pressure range 10-6-10-1 mbar. X-ray photoelectron spectroscopy (XPS), work-function (WF) measurements via a Kelvin probe, LEED and rate measurements were employed as experimental methods. Oxygen adsorption causes a total WF change up to 1.2 eV on the clean surface and up to 1.6 eV on the weakly oxidized surface using the clean surface as a reference level in both cases. On the strongly oxidized surface, the maximum WF change due to chemisorbed oxygen is about 1.8 eV with respect to the WF level of the oxidized surface. XPS measurements of the strongly oxidized, oxygen-saturated surface show two oxygen states characterized by O 1s binding energies of 530.6 and 528.9 eV, with the first state corresponding to the oxide species and chemisorbed oxygen while the second state correlates with the chemisorbed state which is responsible for the large WF increase. Rate measurements during catalytic CO oxidation, which were conducted by varying pCO and pO2 and keeping T fixed, showed the usual clockwise rate hysteresis up to 10-1 mbar with no indication of oscillatory behavior.",
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TY - JOUR

T1 - Characterisation of the oxygen adsorption states on clean and oxidized Ir(110) surfaces

AU - Ladas, S.

AU - Kennou, S.

AU - Hartmann, N.

AU - Imbihl, R.

N1 - Funding Information: The authors gratefully acknowledge financial support from the Volkswagen Foundation, and thank S. Wasle for preparation of the figures.

PY - 1997/6/20

Y1 - 1997/6/20

N2 - The adsorption of O2 and the reaction of CO with O2 have been investigated on a clean as well as on two differently oxidized Ir(110) surfaces in the pressure range 10-6-10-1 mbar. X-ray photoelectron spectroscopy (XPS), work-function (WF) measurements via a Kelvin probe, LEED and rate measurements were employed as experimental methods. Oxygen adsorption causes a total WF change up to 1.2 eV on the clean surface and up to 1.6 eV on the weakly oxidized surface using the clean surface as a reference level in both cases. On the strongly oxidized surface, the maximum WF change due to chemisorbed oxygen is about 1.8 eV with respect to the WF level of the oxidized surface. XPS measurements of the strongly oxidized, oxygen-saturated surface show two oxygen states characterized by O 1s binding energies of 530.6 and 528.9 eV, with the first state corresponding to the oxide species and chemisorbed oxygen while the second state correlates with the chemisorbed state which is responsible for the large WF increase. Rate measurements during catalytic CO oxidation, which were conducted by varying pCO and pO2 and keeping T fixed, showed the usual clockwise rate hysteresis up to 10-1 mbar with no indication of oscillatory behavior.

AB - The adsorption of O2 and the reaction of CO with O2 have been investigated on a clean as well as on two differently oxidized Ir(110) surfaces in the pressure range 10-6-10-1 mbar. X-ray photoelectron spectroscopy (XPS), work-function (WF) measurements via a Kelvin probe, LEED and rate measurements were employed as experimental methods. Oxygen adsorption causes a total WF change up to 1.2 eV on the clean surface and up to 1.6 eV on the weakly oxidized surface using the clean surface as a reference level in both cases. On the strongly oxidized surface, the maximum WF change due to chemisorbed oxygen is about 1.8 eV with respect to the WF level of the oxidized surface. XPS measurements of the strongly oxidized, oxygen-saturated surface show two oxygen states characterized by O 1s binding energies of 530.6 and 528.9 eV, with the first state corresponding to the oxide species and chemisorbed oxygen while the second state correlates with the chemisorbed state which is responsible for the large WF increase. Rate measurements during catalytic CO oxidation, which were conducted by varying pCO and pO2 and keeping T fixed, showed the usual clockwise rate hysteresis up to 10-1 mbar with no indication of oscillatory behavior.

KW - Adsorption kinetics

KW - Catalysis

KW - Iridium

KW - Low index single crystal surfaces

KW - Oxidation

KW - Oxygen

KW - Single crystal surfaces

KW - Work function measurements

KW - X-ray photoelectron spectroscopy

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