Preparation, electrochemical responses and sensing application of Au disk nanoelectrodes down to 5 nm
Preparation, electrochemical responses and sensing application of Au disk nanoelectrodes down to 5 nm
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DOI：
10.1039/c5ra14777h
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发表时间：
2015-09
期刊：
影响因子：
3.9
通讯作者：
Yaoyao Zhang;Shen Xu;Yuanyuan Qian;Xiaosong Yang;Yongxin Li
中科院分区：
文献类型：
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作者：
Yaoyao Zhang;Shen Xu;Yuanyuan Qian;Xiaosong Yang;Yongxin Li
本文报道了通过改进激光辅助拉丝技术制备半径为5nm的金盘纳米电极及其电化学响应。将金微线密封在双层毛细管中，并使用激光辅助拉拔器将其拉入密封在二氧化硅尖端的超尖锐金纳米线中。然后将超锋利的尖端密封在一块玻璃管中，手工抛光以暴露金。利用透射电子显微镜、二茂铁（Fc）、二茂铁甲醇（FcH2OH）、铁氰化钾（Fe(CN)63−）、六胺氯化钌（Ru(NH3)63+）的稳态伏安法和H2SO4溶液中的循环伏安法来表征纳米电极。的异构电子转移速率常数Fc的氧化/还原,FcH2OH, Fe (CN) 63−和俄文(NH3) 63 +决心从稳态伏安法使用方法由墨金和吟游诗人和发现ko = 7.9±3.6厘米−1和α= 0.41±0.04 Fc, ko = 7.4±7.1厘米−1和α= 0.41±0.23,FcCH2OH ko = 4.0±3.6厘米−1和α= 0.52±0.17 Fe (CN) 63−ko = 7.2±6.9厘米−1和α= 0.53±0.22俄文(NH3) 63 +。这些金圆盘纳米电极被用于研究铁蛋白分子的直接电化学反应，铁蛋白分子通过在金表面修饰的半胱胺单层与铁蛋白分子之间的静电相互作用固定在金表面。从Au纳米电极上的铁蛋白伏安峰（半径200 nm）可以计算出~ 3900分子或6.1 zmol的量。
In this work, we report the preparation and electrochemical responses of Au disk nanoelectrodes as small as 5 nm in radii by the improvement of the laser-assisted pulling technique. A Au microwire is sealed into a bilayer capillary and pulled into an ultrasharp Au nanowire sealed in a silica tip using a laser-assisted puller. The ultrasharp tip is then sealed into a piece of glass tube, which is manually polished to expose the Au. Transmission electron microscopy, steady-state voltammetry of small redox species (e.g., ferrocene (Fc), ferrocene methanol (FcH2OH), potassium ferricyanide (Fe(CN)63−), hexaammineruthenium(III)chloride (Ru(NH3)63+)), and cyclic voltammetry in a H2SO4 solution are utilized to characterize the nanoelectrodes. The heterogeneous electron transfer rate constants for the oxidation/reduction of Fc, FcH2OH, Fe(CN)63−, and Ru(NH3)63+ are determined from steady-state voltammetry using the method developed by Mirkin and Bard and found to be ko = 7.9 ± 3.6 cm s−1 and α = 0.41 ± 0.04 for Fc, ko = 7.4 ± 7.1 cm s−1 and α = 0.41 ± 0.23 for FcCH2OH, ko = 4.0 ± 3.6 cm s−1 and α = 0.52 ± 0.17 for Fe(CN)63−, and ko = 7.2 ± 6.9 cm s−1 and α = 0.53 ± 0.22 for Ru(NH3)63+. These Au disk nanoelectrodes have been used to investigate the direct electrochemistry of ferritin molecules, which are immobilized on the Au surface by an electrostatic interaction between the cysteamine monolayer modified on the Au surface and ferritin molecules. From the voltammetric peak of ferritin on the Au nanoelectrode (200 nm in radius), the amount of ∼3900 molecules or 6.1 zmol can be calculated.