Electrochemical Insight into the Brust鈥揝chiffrin Synthesis of Au Nanoparticles

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• 作者：Akihiro Uehara ; Samuel G. Booth ; Sin Yuen Chang ; Sven L. M. Schroeder ; Takahito Imai ; Teruo Hashimoto ; J. Frederick W. Mosselmans ; Robert A. W. Dryfe
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：137
• 期：48
• 页码：15135-15144
• 全文大小：679K
• ISSN：1520-5126

文摘

The mechanism of the Brust鈥揝chiffrin gold nanoparticle synthesis has been investigated through the use of ion transfer voltammetry at the water/1,2-dichloroethane (DCE) solution interface, combined with X-ray absorption fine structure (XAFS) of the reaction between [AuCl₄]^{鈭?/sup> and thiol (RSH) in homogeneous toluene (TL) solution. Ion transfer calculations indicate the formation of [AuCl₂]鈭?/sup> at RSH/Au ratios from 0.2鈥? with a time-dependent variation observed over several days. At RSH/Au ratios above 2 and after time periods greater than 24 h, the formation of Au(I)SR is also observed. The relative concentrations of reaction products observed at the liquid/liquid interface are in excellent agreement with those observed by XAFS for the corresponding reaction in a single homogeneous phase. BH₄鈥?/sup> ion transfer reactions between water and DCE indicate that the reduction of [AuCl₄]鈭?/sup> or [AuCl₂]鈭?/sup> to Au nanoparticles by BH₄鈥?/sup> proceeds in the bulk organic phase. On the other hand, BH₄鈥?/sup> was unable to reduce the insoluble [Au(I)SR]_n species to Au nanoparticles. The number and size of the nanoparticles formed was dependent on the concentration ratio of RSH/Au, as well as the experimental duration because of the competing formation of the [Au(I)SR]_n precipitate. Higher concentrations of nanoparticles, with diameters of 1.0鈥?.5 nm, were formed at RSH/Au ratios from 1 to 2.}