Abbreviated Journal Title
Phys. Rev. B
VIBRATIONAL PROPERTIES; MICELLE ENCAPSULATION; METAL; NANOCRYSTALS; CATALYSTS; CLUSTERS; DISORDER; SURFACE; EXAFS; Physics, Condensed Matter
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.
Physical Review B
Cuenya, B. Roldan; Frenkel, A. I.; Mostafa, S.; Behafarid, F.; Croy, J. R.; Ono, L. K.; and Wang, Q., "Anomalous lattice dynamics and thermal properties of supported size- and shape-selected Pt nanoparticles" (2010). Faculty Bibliography 2010s. 74.