The “Solid Solution” and “Core-shell” Type Structure Control of Silver-Gold
Nanoparticles
Hau-Ming Chen (陳浩銘)1, Ru-Shi Liu (劉如熹)1,
Jyh-Fu Lee (李志甫)2, and Ling-Yun Jang (張凌雲)2
1
2
Department of Chemistry, Taiwan University, Taipei, Taiwan
National Synchrotron Radiation Research Center, Hsinchu, Taiwan
We report the synthesis of “solid solution” and “core-shell” type of Ag-Au nanoalloys smaller
than 10 nm. The core-shell type nanoparticles include AgcoreAushell and inverse structure. The
formation of these nanoparticles is driven by redox transmetalation reactions between the reagents
without adding any reductant. By controlling the synthetic process, we can fabricate the bimetallic
nanoparticles with “solid solution” and “core-shell” structure. The composition of the alloys can
also be tuned by adjusting the ratio of reactants. The characterization of silver-gold bimetallic
nanoparticles by transmission electron microscopy (TEM) and, in particular, X-ray absorption
spectroscopy (XAS) provides clear evidence for the existence of a core-shell type bimetallic
interfacial structure. Extended X-ray absorption fine structure (EXAFS) can provide valuable
structural information about the nanostructure. We extrapolate the distribution of silver and gold
atoms in single particle by analysing the coordination number between silver and gold atoms. The
structure determination is performed by the experimental data of the EXAFS associated with the
L3-edge of gold and the K-edge of silver.
k3x(k)
Au
Ag/Au=4/1
Ag/Au=4/2
Ag/Au=4/3
Ag/Au=4/4
0
2
4
6
8
10
12
k (Å-1)
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[5] T. Shibata, B. A. Bunker, Z. Zhang, D. Meisel, C. F. Vardeman, J. D. Gezelter, J. Am. Chem.
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