Real-Time Imaging of the Formation of Au–Ag Core–Shell Nanoparticles

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• 作者：Shu Fen Tan ; See Wee Chee ; Guanhua Lin ; Michel Bosman ; Ming Lin ; Utkur Mirsaidov ; Christian A. Nijhuis
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：April 27, 2016
• 年：2016
• 卷：138
• 期：16
• 页码：5190-5193
• 全文大小：312K
• 年卷期：0
• ISSN：1520-5126

文摘

We study the overgrowth process of silver-on-gold nanocubes in dilute, aqueous silver nitrate solution in the presence of a reducing agent, ascorbic acid, using in situ liquid-cell electron microscopy. Au–Ag core–shell nanostructures were formed via two mechanistic pathways: (1) nuclei coalescence, where the Ag nanoparticles absorbed onto the Au nanocubes, and (2) monomer attachment, where the Ag atoms epitaxially deposited onto the Au nanocubes. Both pathways lead to the same Au–Ag core–shell nanostructures. Analysis of the Ag deposition rate reveals the growth modes of this process and shows that this reaction is chemically mediated by the reducing agent.