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2664183 
Journal Article 
Ostwald ripening in a Pt/SiO2 model catalyst studied by in situ TEM 
Simonsen, SB; Chorkendorff, Ib; Dahl, S; Skoglundh, M; Sehested, J; Helveg, S 
2011 
Yes 
Journal of Catalysis
ISSN: 0021-9517
EISSN: 1090-2694 
281 
1 
147-155 
WOS:000292488600015 
Sintering of Pt nanoparticles dispersed on a planar SiO2 support was studied by in situ transmission electron microscopy (TEM). A time-lapsed TEM image series of the Pt nanoparticles, acquired during the exposure to 10 mbar synthetic air at 650 degrees C, reveal that the sintering was governed by the Ostwald ripening mechanism. The in situ TEM images also provide information about the temporal evolution of the Pt particle size distribution and of the growth or decay of the individual nanoparticles. The observed Pt nanoparticle changes compare well with predictions made by mean-field kinetic models for ripening, but deviations are revealed for the time-evolution for the individual nanoparticles. A better description of the individual nanoparticle ripening is obtained by kinetic models that include local correlations between neighboring nanoparticles in the atom-exchange process. (C) 2011 Elsevier Inc. All rights reserved. 
Catalyst deactivation; Sintering; Ostwald ripening; Nanoparticles; Pt; In situ TEM