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Title: Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts

Abstract

In this Environmental TEM (ETEM) study of supported Pt and Pd model catalysts, individual nanoparticles were tracked during heat treatments at temperatures up to 600°C in H2, O2, and vacuum. We found anomalous growth of nanoparticles occurred during the early stages of catalyst sintering wherein some particles started to grow significantly larger than the mean, resulting in a broadening of the particle size distribution. We can rule out sample non-uniformity as a cause for the growth of these large particles, since images were recorded prior to heat treatments. The anomalous growth of these particles may help explain particle size distributions in heterogeneous catalysts which often show particles that are significantly larger than the mean, resulting in a long tail to the right. It has been suggested that particle migration and coalescence could be the likely cause for the broad size distributions. This study shows that anomalous growth of nanoparticles can occur under conditions where Ostwald ripening is the primary sintering mechanism.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1056146
Report Number(s):
PNNL-SA-89922
46195
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
ACS Catalysis, 2(11):2349-2356
Additional Journal Information:
Journal Name: ACS Catalysis, 2(11):2349-2356
Country of Publication:
United States
Language:
English
Subject:
ETEM; catalysts; anomalous growth; migration and coalescence; Ostwald; particles; Environmental Molecular Sciences Laboratory

Citation Formats

Benavidez, Angelica D., Kovarik, Libor, Genc, Arda, Agrawal, Nitin, Larsson, Elin M., Hansen, Thomas W., Karim, Ayman M., and Datye, Abhaya K. Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts. United States: N. p., 2012. Web. doi:10.1021/cs3005117.
Benavidez, Angelica D., Kovarik, Libor, Genc, Arda, Agrawal, Nitin, Larsson, Elin M., Hansen, Thomas W., Karim, Ayman M., & Datye, Abhaya K. Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts. United States. doi:10.1021/cs3005117.
Benavidez, Angelica D., Kovarik, Libor, Genc, Arda, Agrawal, Nitin, Larsson, Elin M., Hansen, Thomas W., Karim, Ayman M., and Datye, Abhaya K. Wed . "Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts". United States. doi:10.1021/cs3005117.
@article{osti_1056146,
title = {Environmental Transmission Electron Microscopy Study of the Origins of Anomalous Particle Size Distributions in Supported Metal Catalysts},
author = {Benavidez, Angelica D. and Kovarik, Libor and Genc, Arda and Agrawal, Nitin and Larsson, Elin M. and Hansen, Thomas W. and Karim, Ayman M. and Datye, Abhaya K.},
abstractNote = {In this Environmental TEM (ETEM) study of supported Pt and Pd model catalysts, individual nanoparticles were tracked during heat treatments at temperatures up to 600°C in H2, O2, and vacuum. We found anomalous growth of nanoparticles occurred during the early stages of catalyst sintering wherein some particles started to grow significantly larger than the mean, resulting in a broadening of the particle size distribution. We can rule out sample non-uniformity as a cause for the growth of these large particles, since images were recorded prior to heat treatments. The anomalous growth of these particles may help explain particle size distributions in heterogeneous catalysts which often show particles that are significantly larger than the mean, resulting in a long tail to the right. It has been suggested that particle migration and coalescence could be the likely cause for the broad size distributions. This study shows that anomalous growth of nanoparticles can occur under conditions where Ostwald ripening is the primary sintering mechanism.},
doi = {10.1021/cs3005117},
journal = {ACS Catalysis, 2(11):2349-2356},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {10}
}