Anomalous Structural Disorder in Supported Pt Nanoparticles.
J Phys Chem Lett
; 8(14): 3284-3288, 2017 Jul 20.
Article
in En
| MEDLINE
| ID: mdl-28669195
ABSTRACT
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 here 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. 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.
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01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Phys Chem Lett
Year:
2017
Document type:
Article
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