Oxidation-Resistant Gold-55 Clusters
H.-G. Boyen,1*
G. Kästle,1
F. Weigl,1
B. Koslowski,1
C. Dietrich,1
P. Ziemann,1
J. P. Spatz,3
S. Riethmüller,2
C. Hartmann,2
M. Möller,2
G. Schmid,4
M. G. Garnier,5
P. Oelhafen5
Gold nanoparticles ranging in diameter from 1 to 8 nanometers were prepared on top of silicon wafers in order to study the size dependence of their oxidation behavior when exposed to atomic oxygen. X-ray photoelectron spectroscopy showed a maximum oxidation resistance for "magic-number" clusters containing 55 gold atoms. This inertness is not related to electron confinement leading to a
size-induced metal-to-insulator transition, but rather seems to be
linked to the closed-shell structure of such magic clusters. The result
additionally suggests that gold-55 clusters may act as especially
effective oxidation catalysts, such as for oxidizing carbon monoxide.
1 Abteilung Festkörperphysik,
2 Abteilung Organische Chemie III, Universität
Ulm, D-89069 Ulm, Germany.
3 Physikalisch Chemisches
Institut, Universität Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany.
4 Institut für
Anorganische Chemie, Universität GH Essen,
Universitätsstrasse 5-7, D-45117 Essen, Germany.
5 Institut für Physik, Universität
Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
*
To whom correspondence should be addressed. E-mail:
hans-gerd.boyen{at}physik.uni-ulm.de
