Shape-controlled syntheses of gold nanoprisms and nanorods influenced by specific adsorption of halide ions
Shape-controlled syntheses of gold nanoprisms and nanorods influenced by specific adsorption of halide ions
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DOI：
10.1021/jp066454l
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发表时间：
2007-01-25
影响因子：
3.7
通讯作者：
Chung, Bong Hyun
中科院分区：
文献类型：
--
作者：
Ha, Tai Hwan;Koo, Hee-Joon;Chung, Bong Hyun
以十六烷基三甲基溴化铵(CTAB)为阳离子表面活性剂体系，研究了卤素离子在种子诱导生长纳米金过程中的作用。在生长溶液中加入少量的碘离子(约20µM)，在过量的溴离子(约0.1M)存在下，形成的金纳米结构的主要产物为三角形纳米晶；反之，在过量的溴离子(约0.1M)存在下，主要产物为长径比接近11的纳米棒。碘离子的主要作用是延缓晶体生长的总体速度，而碘离子的吸附抑制了晶体沿Au(111)方向的生长，形成了Au(111)面的三角形纳米晶。当表面活性剂的反阴离子被氯离子取代后，制备了一种新型的纳米结构(即纳米孔洞)，证明了其对卤离子的有效吸附。然而，这一发现与Sastry小组(J·纳诺西)的工作形成了鲜明的对比。纳米替卡诺(Nanotechnol)。2005、5、1721-1727)，其中碘离子强烈抑制纳米颗粒的形成。这些不同的结果归因于还原金前驱体的不同实验条件。然而，总的来说，这些观察表明，卤化物离子的特殊吸附是完全控制种子介导的金晶体生长中的形状发展的一个重要因素。
This paper describes the effect of halide ions during the seed-mediated growth of gold nanoparticles employing cetyltrimethylammonium bromide (CTAB) as a cationic surfactant system. With the addition of a small amount of iodide ion (similar to 20 mu M) in a growth solution, the major product of the gold nanostructures formed were notably changed into triangular nanoprisms in the presence of excessive bromide ion (similar to 0.1 M); other-wise, in its absence, nanorods with an aspect ratio of similar to 11 were the main products. The major role of the iodide ion was in retarding the overall rate of crystal growth, and the iodide adsorption appeared to repress the crystal growth along Au(111) direction, resulting in Au(111)-faced triangular nanoprisms. When the counteranions of the surfactant were replaced with chloride ions, a novel nanostructure (i.e., nanorice) was manufactured, which demonstrates the effectiveness of the adsorption of halide ions. However, this finding is quite contrasted with the work of the Sastry group (J. Nanosci. Nanotechnol. 2005, 5, 1721-1727), wherein iodide ions strongly suppress the formation of nanoprism. The distinctive results are attributed to different experimental conditions for reducing gold precursors. Nonetheless, overall these observations suggest that the specific adsorption of halide ions is an important factor for a complete control over the shape developments in the seed-mediated growth of gold crystals.