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Originally published in Science Express on 6 May 2004
Science 11 June 2004:
Vol. 304. no. 5677, pp. 1639 - 1644
DOI: 10.1126/science.1097513
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Research Articles

Fluctuations and Bistabilities on Catalyst Nanoparticles

V. Johánek,1* M. Laurin,1 A. W. Grant,2 B. Kasemo,2 C. R. Henry,3 J. Libuda1{dagger}

We show that coverage fluctuations on catalyst particles can drastically alter their macroscopic catalytic behavior. Scrutinizing the occurrence of kinetic bistabilities, it is demonstrated by molecular beam experiments on model catalysts that macroscopically observable bistabilities vanish completely with decreasing particle size, as previously predicted by theory. The effect is attributed to fluctuation-induced transitions between two kinetic reaction regimes, with a transition rate controlled by both particle size and surface defects. These results suggest that fluctuation-induced effects represent a general phenomenon affecting the reaction kinetics on nanostructured surfaces.

1 Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
2 Department of Applied Physics, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
3 Centre de Recherche de la Matière Condensée et des Nanosciences–CNRS, Campus de Luminy, Case 913, F-13288 Marseille Cedex 9, France.



* Present address: Department of Chemistry, University of California, Irvine, CA 92697–2025, USA.

{dagger} To whom correspondence should be addressed. E-mail: libuda{at}fhi-berlin.mpg.de

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