Temperature-dependent EXAFS analysis of embedded Pt nanocrystals

R. Giulian; L. L. Araujo; P. Kluth; D. J. Sprouster; C. S. Schnohr; G. J. Foran; M. C. Ridgway

doi:10.1088/0953-8984/21/15/155302

Temperature-dependent EXAFS analysis of embedded Pt nanocrystals

R. Giulian^*, L. L. Araujo, P. Kluth, D. J. Sprouster, C. S. Schnohr, G. J. Foran, M. C. Ridgway

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

20 Citations (Scopus)

Abstract

The vibrational and thermal properties of embedded Pt nanocrystals (NCs) have been investigated with temperature-dependent extended x-ray absorption fine structure (EXAFS) spectroscopy. NCs of diameter 1.8-7.4nm produced by ion implantation in amorphous SiO₂ were analysed over the temperature range 20-295K. An increase in Einstein temperature (∼194K) relative to that of a Pt standard (∼179K) was evident for the smallest NCs while those larger than ∼2.0nm exhibited values comparable to bulk material. Similarly, the thermal expansion of interatomic distances was lowest for small NCs. While the amorphous SiO₂ matrix restricted the thermal expansion of interatomic distances, it did not have a significant influence on the mean vibrational frequency of embedded Pt NCs. Instead, the latter was governed by finite-size effects or, specifically, capillary pressure.

Original language	English
Article number	155302
Journal	Journal of Physics Condensed Matter
Volume	21
Issue number	15
DOIs	https://doi.org/10.1088/0953-8984/21/15/155302
Publication status	Published - 2009

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title = "Temperature-dependent EXAFS analysis of embedded Pt nanocrystals",

abstract = "The vibrational and thermal properties of embedded Pt nanocrystals (NCs) have been investigated with temperature-dependent extended x-ray absorption fine structure (EXAFS) spectroscopy. NCs of diameter 1.8-7.4nm produced by ion implantation in amorphous SiO2 were analysed over the temperature range 20-295K. An increase in Einstein temperature (∼194K) relative to that of a Pt standard (∼179K) was evident for the smallest NCs while those larger than ∼2.0nm exhibited values comparable to bulk material. Similarly, the thermal expansion of interatomic distances was lowest for small NCs. While the amorphous SiO2 matrix restricted the thermal expansion of interatomic distances, it did not have a significant influence on the mean vibrational frequency of embedded Pt NCs. Instead, the latter was governed by finite-size effects or, specifically, capillary pressure.",

author = "R. Giulian and Araujo, {L. L.} and P. Kluth and Sprouster, {D. J.} and Schnohr, {C. S.} and Foran, {G. J.} and Ridgway, {M. C.}",

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T1 - Temperature-dependent EXAFS analysis of embedded Pt nanocrystals

AU - Giulian, R.

AU - Araujo, L. L.

AU - Kluth, P.

AU - Sprouster, D. J.

AU - Schnohr, C. S.

AU - Foran, G. J.

AU - Ridgway, M. C.

PY - 2009

Y1 - 2009

N2 - The vibrational and thermal properties of embedded Pt nanocrystals (NCs) have been investigated with temperature-dependent extended x-ray absorption fine structure (EXAFS) spectroscopy. NCs of diameter 1.8-7.4nm produced by ion implantation in amorphous SiO2 were analysed over the temperature range 20-295K. An increase in Einstein temperature (∼194K) relative to that of a Pt standard (∼179K) was evident for the smallest NCs while those larger than ∼2.0nm exhibited values comparable to bulk material. Similarly, the thermal expansion of interatomic distances was lowest for small NCs. While the amorphous SiO2 matrix restricted the thermal expansion of interatomic distances, it did not have a significant influence on the mean vibrational frequency of embedded Pt NCs. Instead, the latter was governed by finite-size effects or, specifically, capillary pressure.

AB - The vibrational and thermal properties of embedded Pt nanocrystals (NCs) have been investigated with temperature-dependent extended x-ray absorption fine structure (EXAFS) spectroscopy. NCs of diameter 1.8-7.4nm produced by ion implantation in amorphous SiO2 were analysed over the temperature range 20-295K. An increase in Einstein temperature (∼194K) relative to that of a Pt standard (∼179K) was evident for the smallest NCs while those larger than ∼2.0nm exhibited values comparable to bulk material. Similarly, the thermal expansion of interatomic distances was lowest for small NCs. While the amorphous SiO2 matrix restricted the thermal expansion of interatomic distances, it did not have a significant influence on the mean vibrational frequency of embedded Pt NCs. Instead, the latter was governed by finite-size effects or, specifically, capillary pressure.

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DO - 10.1088/0953-8984/21/15/155302

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VL - 21

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

IS - 15

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Temperature-dependent EXAFS analysis of embedded Pt nanocrystals

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