Document Type

Article

Publication Version

Published Version

Publication Date

1994

Journal or Book Title

Journal of physical chemistry

Volume

98

Issue

8

First Page

2148

Last Page

2151

DOI

10.1021/j100059a030

Abstract

Under continuous flow conditions the oscillatory NO + CO reaction on Pt(100) exhibits bistability in the temperature range below 440 K. In this range, an inactive stationary branch coexists with a reactive oscillatory branch. The transition from the inactive branch, which is only metastable, to the truly stable active branch proceeds via propagating reaction fronts. The associated nucleation process has been investigated in the 10-6 mbar range using photoemission electron microscopy (PEEM) as a spatially resolving method. A Pt sample of cylindrical shape whose surface comprises the highly active orientational range between (100) and (3 10) was used as a catalyst. Depending on the degree of supersaturation, both heterogeneous and homogeneous nucleation have been found. Homogeneous nucleation manifests itself in the occurrence of a so-called “surface explosion” at Tc = 440 K. Below this temperature, heterogeneous nucleation occurs. Depending on the preparation of the inactive state, we observe two different nucleation scenarios which we can tentatively assign to two different kinds of defects.

Comments

Reprinted (adapted) with permission from Journal of Physical Chemistry 98 (1994): 2148, doi: 10.1021/j100059a030. Copyright 1994 American Chemical Society.

Copyright Owner

American Chemical society

Language

en

File Format

application/pdf

Included in

Chemistry Commons

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