Details
| Original language | English |
|---|---|
| Pages (from-to) | 191-203 |
| Number of pages | 13 |
| Journal | Surface science |
| Volume | 421 |
| Issue number | 1-2 |
| Publication status | Published - 4 Feb 1999 |
Abstract
H/D-isotope effects in chemical wave propagation in the bistable O2+H2 reaction on Rh(110) and Rh(111) and in the excitable NO+H2 reaction on Rh(110) were investigated using photoemission electron microscopy (PEEM) as spatially resolving method. The systems were studied in the 10-6-10-4 mbar range between 400K and 700K. For equivalent partial pressures, i.e., partial pressures which have been corrected for the different impingement rates of H2 and D2, front and pulse propagation with H2 is typically faster than with D2 up to a factor of three. A similar difference exists with respect to the width of the existence range for pattern formation in pH2(D2), which is broader with D2 than with H2. Titration experiments of the oxygen-covered Rh(110) surface demonstrated that at high oxygen coverages, the reactive sticking of D2 is inhibited much more strongly than with H2. From the T-dependence of the front velocities, apparent activation energies were determined for the two isotopes.
Keywords
- Catalysis, Hydrogen, Nitrogen oxides, Oxygen, Pattern formation, Photoemission electron microscopy (PEEM), Rhodium, Single crystal surfaces, Surface chemical reaction, Surface diffusion
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. 421, No. 1-2, 04.02.1999, p. 191-203.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - H/D-isotope effects in chemical wave propagation on surfaces
T2 - The O2+H2 and NO+H2 reactions on Rh(110) and Rh(111)
AU - Schaak, A.
AU - Shaikhutdinov, S.
AU - Imbihl, R.
PY - 1999/2/4
Y1 - 1999/2/4
N2 - H/D-isotope effects in chemical wave propagation in the bistable O2+H2 reaction on Rh(110) and Rh(111) and in the excitable NO+H2 reaction on Rh(110) were investigated using photoemission electron microscopy (PEEM) as spatially resolving method. The systems were studied in the 10-6-10-4 mbar range between 400K and 700K. For equivalent partial pressures, i.e., partial pressures which have been corrected for the different impingement rates of H2 and D2, front and pulse propagation with H2 is typically faster than with D2 up to a factor of three. A similar difference exists with respect to the width of the existence range for pattern formation in pH2(D2), which is broader with D2 than with H2. Titration experiments of the oxygen-covered Rh(110) surface demonstrated that at high oxygen coverages, the reactive sticking of D2 is inhibited much more strongly than with H2. From the T-dependence of the front velocities, apparent activation energies were determined for the two isotopes.
AB - H/D-isotope effects in chemical wave propagation in the bistable O2+H2 reaction on Rh(110) and Rh(111) and in the excitable NO+H2 reaction on Rh(110) were investigated using photoemission electron microscopy (PEEM) as spatially resolving method. The systems were studied in the 10-6-10-4 mbar range between 400K and 700K. For equivalent partial pressures, i.e., partial pressures which have been corrected for the different impingement rates of H2 and D2, front and pulse propagation with H2 is typically faster than with D2 up to a factor of three. A similar difference exists with respect to the width of the existence range for pattern formation in pH2(D2), which is broader with D2 than with H2. Titration experiments of the oxygen-covered Rh(110) surface demonstrated that at high oxygen coverages, the reactive sticking of D2 is inhibited much more strongly than with H2. From the T-dependence of the front velocities, apparent activation energies were determined for the two isotopes.
KW - Catalysis
KW - Hydrogen
KW - Nitrogen oxides
KW - Oxygen
KW - Pattern formation
KW - Photoemission electron microscopy (PEEM)
KW - Rhodium
KW - Single crystal surfaces
KW - Surface chemical reaction
KW - Surface diffusion
UR - http://www.scopus.com/inward/record.url?scp=0033521828&partnerID=8YFLogxK
U2 - 10.1016/S0039-6028(98)00855-3
DO - 10.1016/S0039-6028(98)00855-3
M3 - Article
AN - SCOPUS:0033521828
VL - 421
SP - 191
EP - 203
JO - Surface science
JF - Surface science
SN - 0039-6028
IS - 1-2
ER -