Direct Observations of Oxygen-induced Platinum Nanoparticle Ripening Studied by In Situ TEM
Journal article, 2010

This study addresses the sintering mechanism of Pt nanoparticles dispersed on a planar, amorphous Al2O3 support as a model system for a catalyst for automotive exhaust abatement. By means of in situ transmission electron microscopy (TEM), the model catalyst was monitored during the exposure to 10 mbar air at 650 degrees C. Time-resolved image series unequivocally reveal that the sintering of Pt nanoparticles was mediated by an Ostwald ripening process. A statistical analysis of an ensemble of Pt nanoparticles shows that the particle size distributions change shape from an initial Gaussian distribution via a log-normal distribution to a Lifshitz-Slyozov-Wagner (LSW) distribution. Furthermore, the time-dependency of the ensemble-averaged particle size and particle density is determined. A mean field kinetic description captures the main trends in the observed behavior. However, at the individual nanoparticle level, deviations from the model are observed suggesting in part that the local environment influences the atom exchange process.

size distributions

supported metal-catalysts

transmission electron-microscopy

au particles

steam-reforming catalysts

surface

redispersion

growth-kinetics

diffusion

sintering mechanism

Author

S. B. Simonsen

Haldor Topsoe

Technical University of Denmark (DTU)

I. Chorkendorff

Technical University of Denmark (DTU)

S. Dahl

Technical University of Denmark (DTU)

Magnus Skoglundh

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Competence Centre for Catalysis (KCK)

J. Sehested

Haldor Topsoe

S. Helveg

Haldor Topsoe

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 132 23 7968-7975

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Transport

Energy

Materials Science

Subject Categories

Chemical Engineering

Chemical Sciences

DOI

10.1021/ja910094r

More information

Latest update

3/27/2018