Silver Nanoparticles Stabilized with Thiols: A Close Look at the Local Chemistry and Chemical Structure

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• 作者：Chiara Battocchio ; Carlo Meneghini ; Ilaria Fratoddi ; Iole Venditti ; Maria Vittoria Russo ; Giuliana Aquilanti ; Chiara Maurizio ; Federica Bondino ; Roberto Matassa ; Marco Rossi ; Settimio Mobilio ; Giovanni Polzonetti
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 13, 2012
• 年：2012
• 卷：116
• 期：36
• 页码：19571-19578
• 全文大小：402K
• 年卷期：v.116,no.36(September 13, 2012)
• ISSN：1932-7455

文摘

The local atomic structure and chemical nature of newly synthesized silver nanoparticles (AgNPs) functionalized with the organic thiol allylmercaptane (AM) have been probed combining synchrotron radiation-based techniques: X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure spectroscopy (XAFS). Complementary information about the chemical and electronic structure is obtained combining XAFS and XPS data. These results coherently suggest a core shell morphology of the NPs resulting in metallic Ag cores surrounded by Ag₂S-like phase. The external layer of AM molecules is grafted to the NPs surface through Ag鈥揝 chemical bonds. NP size and composition were found as a function of the chemical synthetic route (i.e., Ag/AM molar ratio). It was observed that by increasing the Ag/AM ratio, larger AgNPs were obtained. It was found that a higher Ag/AM molar ratio leads to an increasing of the Ag₂S layer thickness, while the external AM layer remains unvaried. TEM analysis showed well-separated and dispersed nanoparticles, and ED pattern allowed one to identify two different phases of single crystal corresponding to the presence of Ag face-center-cubic single-crystal symmetry, together with weak diffraction spots in agreement with Ag₂S cubic symmetry in Im3m space groups.