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Summary: CO Oxidation on Aun/TiO2 Catalysts Produced by Size-Selected Cluster
Deposition
Sungsik Lee, Chaoyang Fan, Tianpin Wu, and Scott L. Anderson*
Department of Chemistry, UniVersity of Utah, 315 S. 1400 E. Rm 2020, Salt Lake City, Utah 84112
Received January 30, 2004; E-mail: anderson@chem.utah.edu
Since the discovery that supported gold nanoparticles show
surprising catalytic activity,1 considerable effort has gone into
probing the effects of particle size. For bulk catalysts, peak activity
is typically found for particle sizes in the 2-5 nm range (hundreds
to thousands of atoms), as measured by transmission electron
microscopy (TEM). TEM is insensitive to particles smaller than
1 nm and may overlook smaller active species. Indeed, Fu et al.2
recently showed that activity for the water gas shift reaction on
Au/CeO2 and Pt/CeO2 catalysts was unchanged when the nano-
particles were removed, leaving only ionic metal species on the
surface. There have been a number of planar model catalyst studies
where Au particles are grown on single crystal or thin film oxide,
with size characterized by STM.3-5 CO oxidation on Au/rutile TiO2
(110) has been particularly well studied, and activities typically
are found to peak for Aun in the few nanometer size range. Such
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