TY - JOUR

T1 - Ostwald ripening in a Pt/SiO2 model catalyst studied by in situ TEM

A1 - Simonsen,Søren Bredmose

A1 - Chorkendorff,Ib

A1 - Dahl,Søren

A1 - Skoglundh,Magnus

A1 - Sehested,Jens

A1 - Helveg,Stig

AU - Simonsen,Søren Bredmose

AU - Chorkendorff,Ib

AU - Dahl,Søren

AU - Skoglundh,Magnus

AU - Sehested,Jens

AU - Helveg,Stig

PB - Academic Press

PY - 2011

Y1 - 2011

N2 - 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 10mbar synthetic air at 650°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.

AB - 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 10mbar synthetic air at 650°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.

KW - Sintering

KW - Pt

KW - Ostwald ripening

KW - Nanoparticles

KW - In situ TEM

KW - Catalyst deactivation

U2 - 10.1016/j.jcat.2011.04.011

DO - 10.1016/j.jcat.2011.04.011

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 0021-9517

IS - 1

VL - 281

SP - 147

EP - 155

ER -