Anomalous Lattice Dynamics and Thermal Properties of Supported Size- and Shape-selected Pt Nanoparticles
Anomalous lattice dynamics and thermal behavior have been observed for ligand-free, size-, and shape-selected Pt nanoparticles (NPs) supported on nanocrystalline {gamma}-Al{sub 2}O{sub 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}{sub 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}{sub D} values.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1042112
- Report Number(s):
- BNL-97790-2012-JA; TRN: US1202738
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 15
- Country of Publication:
- United States
- Language:
- English
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