New Findings for the Composition and Structure of Ni Nanoparticles Protected with Organomercaptan Molecules
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- 作者：Mat铆as F. Calder贸n ; Eugenia Zelaya ; Guillermo A. Benitez ; Patricia L. Schilardi ; Alberto Hern谩ndez Creus ; Alejandro Gonz谩lez Orive ; Roberto C. Salvarezza ; Francisco J. Iba帽ez
- 刊名：Langmuir
- 出版年：2013
- 出版时间：April 16, 2013
- 年：2013
- 卷：29
- 期：15
- 页码：4670-4678
- 全文大小：525K
- 年卷期：v.29,no.15(April 16, 2013)
- ISSN：1520-5827
文摘
Here we explore the synthesis of alkanethiol-coated Ni NPs following the one-phase reaction method by Brust et al.click="showRef(event, 'ref1'); return false;" href="JavaScript:void(0);" class="ref">(1) The reduction of NiCl2 with NaBH4 in the presence of dodecanethiol (C12SH) yields a complex product that is difficult to identify as illustrated in the figure of merit. We synthesized Ni(II) dodecanethiolate (C12S) (without the addition of NaBH4) for comparison and performed an exhaustive characterization with TEM, HR-TEM, AFM, MFM, XPS, XRD, UV鈥搗is, magnetism, and FT-IR. It is found that the organic coating is not quite a well-organized self-assembled monolayer (SAM) surrounding the Ni cluster as previously reported.click="showRef(event, 'ref2 ref3'); return false;" href="JavaScript:void(0);" class="ref">(2, 3) XPS and XRD data show slight differences between both syntheses; however, Ni(II) thiolate appears to be more stable than reduced Ni when exposed to ambient air, indicating the propensity of metallic Ni to oxidize. It has been shown that irradiating with TEM electrons over various metal thiolates leads to nanoparticle formation.click="showRef(event, 'ref4'); return false;" href="JavaScript:void(0);" class="ref">(4) We irradiated over Ni(II) thiolate and observed no evidence of NP formation whereas irradiating a reduced Ni sample exhibited an 3.0 nm nanoparticle diameter. Magnetism studies showed a difference between both samples, indicating ferromagnetic character for the reduced Ni sample. According to our results, the product of the synthesis is comprised of ultrasmall metallic clusters embedded in some form of Ni(II) C12S. In this work, we open a discussion of the chemical nature of the core and the shell in the synthesis of Ni NPs protected with organomercaptan molecules.