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

• Sintering of Pt nanoparticles dispersed on a planar SiO(2) 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.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

platinum/silica catalysts

p19

size

Sintering

gamma-al2o3

en m

In situ TEM

lean m

p2401

critical radius

1988

p348

1971

1967

transmission electron-microscopy

1978

thin-films

distributions

cabe rw

Pt

oxidation

Catalyst deactivation

v55

Nanoparticles

v6

mechanisms

v28

p354

akrave.bk

supported metal-catalysts

v114

2-dimensional islands

Ostwald ripening

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)