Relating rates of catalyst sintering to the disappearance of individual nanoparticles during Ostwald ripening

Sivakumar R Challa; Andrew T Delariva; Thomas W Hansen; Stig Helveg; Jens Sehested; Poul L Hansen; Fernando Garzon; Abhaya K Datye

doi:10.1021/ja208324n

Relating rates of catalyst sintering to the disappearance of individual nanoparticles during Ostwald ripening

J Am Chem Soc. 2011 Dec 28;133(51):20672-5. doi: 10.1021/ja208324n. Epub 2011 Dec 1.

Authors

Sivakumar R Challa¹, Andrew T Delariva, Thomas W Hansen, Stig Helveg, Jens Sehested, Poul L Hansen, Fernando Garzon, Abhaya K Datye

Affiliation

¹ University of New Mexico, Albuquerque, New Mexico 87131, USA.

PMID: 22087502
DOI: 10.1021/ja208324n

Abstract

Sintering of nanoparticles (NPs) of Ni supported on MgAl(2)O(4) was monitored in situ using transmission electron microscopy (TEM) during exposure to an equimolar mixture of H(2) and H(2)O at a pressure of 3.6 mbar at 750 °C, conditions relevant to methane steam reforming. The TEM images revealed an increase in the mean particle size due to disappearance of smaller, immobile NPs and the resultant growth of the larger NPs. A new approach for predicting the long-term sintering of NPs is presented wherein microscopic observations of the ripening of individual NPs (over a span of a few seconds) are used to extract energetic parameters that allow a description of the collective behavior of the entire population of NPs (over several tens of minutes).