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Title: Anomalous Structural Disorder in Supported Pt Nanoparticles

Supported Pt nanocatalysts generally exhibit anomalous behavior, including negative thermal expansion and large structural disorder. Finite temperature DFT/MD simulations reproduce these properties, showing that they are largely explained by a combination of thermal vibrations and low-frequency disorder. We show in this paper that a full interpretation is more complex and that the DFT/MD mean-square relative displacements (MSRD) can be further separated into vibrational disorder, “dynamic structural disorder” (DSD), and long-time equilibrium fluctuations of the structure dubbed “anomalous structural disorder” (ASD). We find that the vibrational and DSD components behave normally, increasing linearly with temperature while the ASD decreases, reflecting the evolution of mean nanoparticle geometry. Finally, as a consequence the usual procedure of fitting the MSRD to normal vibrations plus temperature-independent static disorder results in unphysical bond strengths and Grüneisen parameters.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ; ORCiD logo [3]
  1. Univ. of Washington, Seattle, WA (United States)
  2. Univ. of Illinois, Urbana, IL (United States)
  3. Stony Brook Univ., NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
BNL-114357-2017-JA
Journal ID: ISSN 1948-7185; YN0100000
Grant/Contract Number:
SC0012704; FG02-03ER15476; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 8; Journal Issue: 14; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
Univ. of Illinois at Urbana-Champaign, IL (United States); Univ. of Washington, Seattle, WA (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1395941

Vila, Fernando D., Rehr, John J., Nuzzo, Ralph G., and Frenkel, Anatoly I.. Anomalous Structural Disorder in Supported Pt Nanoparticles. United States: N. p., Web. doi:10.1021/acs.jpclett.7b01446.
Vila, Fernando D., Rehr, John J., Nuzzo, Ralph G., & Frenkel, Anatoly I.. Anomalous Structural Disorder in Supported Pt Nanoparticles. United States. doi:10.1021/acs.jpclett.7b01446.
Vila, Fernando D., Rehr, John J., Nuzzo, Ralph G., and Frenkel, Anatoly I.. 2017. "Anomalous Structural Disorder in Supported Pt Nanoparticles". United States. doi:10.1021/acs.jpclett.7b01446. https://www.osti.gov/servlets/purl/1395941.
@article{osti_1395941,
title = {Anomalous Structural Disorder in Supported Pt Nanoparticles},
author = {Vila, Fernando D. and Rehr, John J. and Nuzzo, Ralph G. and Frenkel, Anatoly I.},
abstractNote = {Supported Pt nanocatalysts generally exhibit anomalous behavior, including negative thermal expansion and large structural disorder. Finite temperature DFT/MD simulations reproduce these properties, showing that they are largely explained by a combination of thermal vibrations and low-frequency disorder. We show in this paper that a full interpretation is more complex and that the DFT/MD mean-square relative displacements (MSRD) can be further separated into vibrational disorder, “dynamic structural disorder” (DSD), and long-time equilibrium fluctuations of the structure dubbed “anomalous structural disorder” (ASD). We find that the vibrational and DSD components behave normally, increasing linearly with temperature while the ASD decreases, reflecting the evolution of mean nanoparticle geometry. Finally, as a consequence the usual procedure of fitting the MSRD to normal vibrations plus temperature-independent static disorder results in unphysical bond strengths and Grüneisen parameters.},
doi = {10.1021/acs.jpclett.7b01446},
journal = {Journal of Physical Chemistry Letters},
number = 14,
volume = 8,
place = {United States},
year = {2017},
month = {7}
}