Synthesis of Atomically Ordered AuCu and AuCu3 Nanocrystals from Bimetallic Nanoparticle Precursors
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- 作者：Amandeep K. Sra and Raymond E. Schaak
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：June 2, 2004
- 年：2004
- 卷：126
- 期：21
- 页码：6667 - 6672
- 全文大小：390K
- 年卷期：v.126,no.21(June 2, 2004)
- ISSN：1520-5126
文摘
A new multistep approach was developed to synthesize atomically ordered intermetallicnanocrystals, using AuCu and AuCu3 as model systems. Bimetallic nanoparticle aggregates are used asprecursors to atomically ordered nanocrystals, both to precisely define the stoichiometry of the final productand to ensure that atomic-scale diffusion distances lower the reaction temperatures to prevent sintering. Ina typical synthesis, PVP-stabilized Au-Cu nanoparticle aggregates synthesized by borohydride reductionare collected by centrifugation and annealed in powder form. At temperatures below 175 
C, diffusion ofCu into Au occurs, and the atomically disordered solid solution CuxAu1-x exists. For AuCu, nucleation occursby 200 C, and atomically ordered AuCu exists between 200 and 400 C. For AuCu3, an AuCu intermediatenucleates at 200 C, and further diffusion of Cu into the AuCu intermediate at 300 C nucleates AuCu3.Atomically ordered AuCu and AuCu3 nanocrystals can be redispersed as discrete colloids in solution afterannealing between 200 and 300 C.
C, diffusion ofCu into Au occurs, and the atomically disordered solid solution CuxAu1-x exists. For AuCu, nucleation occursby 200 C, and atomically ordered AuCu exists between 200 and 400 C. For AuCu3, an AuCu intermediatenucleates at 200 C, and further diffusion of Cu into the AuCu intermediate at 300 C nucleates AuCu3.Atomically ordered AuCu and AuCu3 nanocrystals can be redispersed as discrete colloids in solution afterannealing between 200 and 300 C.