Iodide in CTAB Prevents Gold Nanorod Formation
Iodide in CTAB Prevents Gold Nanorod Formation
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DOI：
10.1021/la900757s
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发表时间：
2009-08-18
期刊：
影响因子：
3.9
通讯作者：
Korgel, Brian A.
中科院分区：
文献类型：
--
作者：
Smith, Danielle K.;Miller, Nathan R.;Korgel, Brian A.
使用十六烷基三甲基溴化铵（CTAB）作为稳定表面活性剂的金纳米晶体种子介导方法通常用于制造大量单分散金纳米棒。然而，这种方法有时很难在不同的实验室中重现。我们最近展示了[Smith, D. K,; Korgel, B. A. Langmuir 2008, 24, 644-649]从一些供应商处获得的 CTAB 中浓度极低的杂质会阻止纳米棒的生长，但无法识别该杂质。在这里，我们报告该杂质是碘化物。电感耦合等离子体质谱 (ICP-MS) 显示，不同供应商生产的 CTAB 中的碘化物浓度各不相同，从低于 2.75 ppm 到高达 840 ppm。当使用碘化物浓度大于 50 ppm 的 CTAB 时，不会形成纳米棒，并且产品完全由球形纳米晶体组成。碘化物减缓 Au(III) 向 Au-0 的还原。 Au {111} 表面上的碘化物吸附抑制纳米棒的生长。
The gold nanocrystal seed-mediated approach using cetyltrimethylammonium bromide (CTAB) as a stabilizing surfactant is commonly used to make large quantities of monodisperse gold nanorods. This method, however, has been at times difficult to reproduce in different laboratories. We recently showed [Smith, D. K,; Korgel, B. A. Langmuir 2008, 24, 644-649] that a very low concentration impurity in CTAB obtained from some suppliers prevents nanorod growth but were not able to identify the impurity. Here, we report that the impurity is iodide. Inductively coupled plasma mass spectroscopy (ICP-MS) revealed that iodide concentrations vary in CTAB from different suppliers, from less than 2.75 ppm up to 840 ppm. When CTAB with iodide concentrations greater than 50 ppm is used, nanorods do not form and the product consists entirely of spherical nanocrystals. Iodide slows the reduction of Au(III) to Au-0. Iodide adsorption on Au {111} surfaces inhibits nanorod growth.