Size-dependent melting of silica-encapsulated gold nanoparticles

Kimberly Dick, Dhanasekaran Thirunavukkarasu, Zhenyuan Zhang, Dan Meisel

Research output: Contribution to journalArticle

425 Citations (Scopus)

Abstract

We report on the size dependence of the melting temperature of silica-encapsulated gold nanoparticles. The melting point was determined using differential thermal analysis (DTA) coupled to thermal gravimetric analysis (TGA) techniques. The small gold particles, with sizes ranging from 1.5 to 20 nm, were synthesized using radiolytic and chemical reduction procedures and then coated with porous silica shells to isolate the particles from one another. The resulting silica-encapsulated gold particles show clear melting endotherms in the DTA scan with no accompanying weight loss of the material in the TGA examination. The silica shell acts as a nanocrucible for the melting gold with little effect on the melting temperature itself, even though the analytical procedure destroys the particles once they melt. Phenomenological thermodynamic predictions of the size dependence of the melting point of gold agree with the experimental observation. Implications of these observations to the self-diffusion coefficient of gold in the nanoparticles are discussed, especially as they relate to the spontaneous alloying of core - shell bimetallic particles.

Original languageEnglish
Pages (from-to)2312-2317
Number of pages6
JournalJournal of the American Chemical Society
Volume124
Issue number10
DOIs
Publication statusPublished - 13 Mar 2002
Externally publishedYes

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Silicon Dioxide
Gold
Nanoparticles
Freezing
Melting
Silica
Melting point
Differential Thermal Analysis
Gravimetric analysis
Differential thermal analysis
Hot Temperature
Temperature
Thermodynamics
Alloying
Particle Size
Weight Loss
Observation

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Size-dependent melting of silica-encapsulated gold nanoparticles. / Dick, Kimberly; Thirunavukkarasu, Dhanasekaran; Zhang, Zhenyuan; Meisel, Dan.

In: Journal of the American Chemical Society, Vol. 124, No. 10, 13.03.2002, p. 2312-2317.

Research output: Contribution to journalArticle

Dick, Kimberly ; Thirunavukkarasu, Dhanasekaran ; Zhang, Zhenyuan ; Meisel, Dan. / Size-dependent melting of silica-encapsulated gold nanoparticles. In: Journal of the American Chemical Society. 2002 ; Vol. 124, No. 10. pp. 2312-2317.
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