Anomalous Vibrational Properties Induced by Surface Effects in Capped Pt Nanoparticles

LISANDRO J. GIOVANETTI; JOSÉ M. RAMALLO-LÓPEZ; FÉLIX G. REQUEJO; DOMINGO I. GARCIA-GUTIERREZ; MIGUEL JOSE-YACAMAN; ALDO F. CRAIEVICH

The Journal of Physical Chemistry C

ACS

Lugar: Washington; Año: 2007 p. 7599 - 7604

1932-7447

The Debye temperature of Pt nanoparticles (NP) capped in PVP-K30 with an average diameter of 3 nm was determined from extended X-ray absorption fine structure measurements between 20 and 373 K. The size distribution of the NP was determined by high-resolution transmission electron microscopy, high-angle annular dark field, and small-angle X-ray scattering. We have experimentally established that the Debye temperature of truncated cuboctahedron, capped Pt NP is 70 K higher than that of bulk Pt metal. The rather high value of the Debye temperature of nanosized-capped Pt crystals is related to surface Pt-Pt contraction effects in conjunction with capping interactions. This finding evidences that the vibrational behavior of nanostructure materials differs markedly from that of materials in bulk form.