Details
| Original language | English |
|---|---|
| Pages (from-to) | 49-56 |
| Number of pages | 8 |
| Journal | Surface science |
| Volume | 382 |
| Issue number | 1-3 |
| Publication status | Published - 20 Jun 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.
Keywords
- Adsorption kinetics, Catalysis, Iridium, Low index single crystal surfaces, Oxidation, Oxygen, Single crystal surfaces, Work function measurements, X-ray photoelectron spectroscopy
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Materials Chemistry
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In: Surface science, Vol. 382, No. 1-3, 20.06.1997, p. 49-56.
Research output: Contribution to journal › Article › Research › peer review
}
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
UR - http://www.scopus.com/inward/record.url?scp=0031167486&partnerID=8YFLogxK
U2 - 10.1016/S0039-6028(97)00095-2
DO - 10.1016/S0039-6028(97)00095-2
M3 - Article
AN - SCOPUS:0031167486
VL - 382
SP - 49
EP - 56
JO - Surface science
JF - Surface science
SN - 0039-6028
IS - 1-3
ER -