Details
| Original language | English |
|---|---|
| Pages (from-to) | L477-L483 |
| Journal | Surface science |
| Volume | 405 |
| Issue number | 1 |
| Publication status | Published - 12 May 1998 |
Abstract
Field electron microscopy (FEM) is employed to monitor local brightness fluctuations that occur during catalytic CO oxidation on a Pt field emitter tip and that are caused by local variations in the adsorbate coverages. The reaction is studied in the bistability range at T = 310 K with fixed po2 = 4.0 x 10-4 Torr and pCO = 3.0 x 10-7 Torr. The measurements are conducted on the apex plane of a [100]-oriented Pt tip. Local time series are obtained by digitization of the video-recorded FEM image (40 ms time resolution) and integration of the intensity in windows of 100 x 100 Å and 20 x 100 Å size. From the measured time series, the autocorrelation and cross-correlation functions were determined. Fluctuations on the reactive (oxygen covered) and on the inactive (CO covered) branch of the reaction exhibit quite substantial differences. On the reactive branch, spatial correlations extend over much longer distances (several hundred angstroms) than on the unreactive branch, and time correlations decay much more slowly. These differences are discussed on the basis of the Langmuir-Hinshelwood mechanism for catalytic CO oxidation. The fluctuations on the unreactive branch apparently originate from CO diffusion alone.
Keywords
- Carbon monoxide, Field emission, Oxidation, Oxygen, Platinum, Surface chemical reaction
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. 405, No. 1, 12.05.1998, p. L477-L483.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Local fluctuations during catalytic CO oxidation on Pt
T2 - A field emission study
AU - Suchorski, Yu
AU - Beben, J.
AU - Imbihl, R.
N1 - Funding Information: Financial support from the Deutsche For-schungsgemeinschaft is gratefully acknowledged.
PY - 1998/5/12
Y1 - 1998/5/12
N2 - Field electron microscopy (FEM) is employed to monitor local brightness fluctuations that occur during catalytic CO oxidation on a Pt field emitter tip and that are caused by local variations in the adsorbate coverages. The reaction is studied in the bistability range at T = 310 K with fixed po2 = 4.0 x 10-4 Torr and pCO = 3.0 x 10-7 Torr. The measurements are conducted on the apex plane of a [100]-oriented Pt tip. Local time series are obtained by digitization of the video-recorded FEM image (40 ms time resolution) and integration of the intensity in windows of 100 x 100 Å and 20 x 100 Å size. From the measured time series, the autocorrelation and cross-correlation functions were determined. Fluctuations on the reactive (oxygen covered) and on the inactive (CO covered) branch of the reaction exhibit quite substantial differences. On the reactive branch, spatial correlations extend over much longer distances (several hundred angstroms) than on the unreactive branch, and time correlations decay much more slowly. These differences are discussed on the basis of the Langmuir-Hinshelwood mechanism for catalytic CO oxidation. The fluctuations on the unreactive branch apparently originate from CO diffusion alone.
AB - Field electron microscopy (FEM) is employed to monitor local brightness fluctuations that occur during catalytic CO oxidation on a Pt field emitter tip and that are caused by local variations in the adsorbate coverages. The reaction is studied in the bistability range at T = 310 K with fixed po2 = 4.0 x 10-4 Torr and pCO = 3.0 x 10-7 Torr. The measurements are conducted on the apex plane of a [100]-oriented Pt tip. Local time series are obtained by digitization of the video-recorded FEM image (40 ms time resolution) and integration of the intensity in windows of 100 x 100 Å and 20 x 100 Å size. From the measured time series, the autocorrelation and cross-correlation functions were determined. Fluctuations on the reactive (oxygen covered) and on the inactive (CO covered) branch of the reaction exhibit quite substantial differences. On the reactive branch, spatial correlations extend over much longer distances (several hundred angstroms) than on the unreactive branch, and time correlations decay much more slowly. These differences are discussed on the basis of the Langmuir-Hinshelwood mechanism for catalytic CO oxidation. The fluctuations on the unreactive branch apparently originate from CO diffusion alone.
KW - Carbon monoxide
KW - Field emission
KW - Oxidation
KW - Oxygen
KW - Platinum
KW - Surface chemical reaction
UR - http://www.scopus.com/inward/record.url?scp=0032071017&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0032071017
VL - 405
SP - L477-L483
JO - Surface science
JF - Surface science
SN - 0039-6028
IS - 1
ER -