Title

Anomalous lattice dynamics and thermal properties of supported size- and shape-selected Pt nanoparticles

Authors

Authors

B. R. Cuenya; A. I. Frenkel; S. Mostafa; F. Behafarid; J. R. Croy; L. K. Ono;Q. Wang

Comments

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Abbreviated Journal Title

Phys. Rev. B

Keywords

VIBRATIONAL PROPERTIES; MICELLE ENCAPSULATION; METAL; NANOCRYSTALS; CATALYSTS; CLUSTERS; DISORDER; SURFACE; EXAFS; Physics, Condensed Matter

Abstract

Anomalous lattice dynamics and thermal behavior have been observed for ligand-free, size-, and shape-selected Pt nanoparticles (NPs) supported on nanocrystalline gamma-Al(2)O(3) via extended x-ray absorption fine-structure spectroscopy. Several major differences were observed for the NPs with respect to bulk Pt: (i) a contraction in the interatomic distances, (ii) a reduction in the dynamic (temperature-dependent) bond-length disorder and associated increase in the Debye temperature (theta(D)), and (iii) an overall decrease in the bond-length expansion coefficient coupled with NP stiffening. The increase in the Debye temperature is explained in terms of the NP size, shape, support interactions, and adsorbate effects. For a similar average size, we observe a striking correlation between the shapes of the NPs and their theta(D) values.

Journal Title

Physical Review B

Volume

82

Issue/Number

15

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

8

WOS Identifier

WOS:000283575600003

ISSN

1098-0121

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