Self-assembly and electrochemical desorption of thioctic acid monolayers on gold surfaces
Self-assembly and electrochemical desorption of thioctic acid monolayers on gold surfaces
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DOI：
10.1021/la0261141
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发表时间：
2003-10-14
期刊：
影响因子：
3.9
通讯作者：
Bozack, MJ
中科院分区：
文献类型：
--
作者：
Dong, YZ;Abaci, S;Bozack, MJ
采用电化学脱附实验和X射线光电子能谱研究了硫辛酸（1，2-二硫戊环-3-戊酸）在Au表面的自组装单分子膜。在0.5 M KOH电解液中，从Au电极上阴极剥离硫辛酸单分子膜具有两个脱附特征。第一个，集中在-0.93 V（相对于Ag/AgCl），是在很好的协议与早期的研究在Au上的硫辛酸单分子膜。第二个峰出现在约-1.27 V处，据我们所知，以前没有报道过。动力学研究，其中电化学解吸曲线和XPS光谱记录为总的自组装时间从1分钟到2周不等，揭示了两种不同的吸附状态的硫辛酸在金表面上。第一个伏安波（-0.93V）与硫辛酸本身的解吸有关，第二个是由于氧化的硫辛酸（以二亚磺酸盐和二磺酸盐的形式存在）的解吸。最后，通过两种合成路线制备了氧化TA，并形成氧化TA的自组装单分子膜。电化学解吸实验显示在-1.27 V处的单一解吸波，证实了我们的分配。
Self-assembled monolayers of thioctic acid (1,2-dithiolane-3-pentanoic acid) on Au surfaces were studied by electrochemical desorption experiments and X-ray photoelectron spectroscopy. The cathodic stripping of thioctic acid monolayers from Au electrodes in 0.5 M KOH electrolyte is characterized by two desorption features. The first, centered at -0.93 V (vs Ag/AgCl), is in good agreement with earlier studies of thioctic acid monolayers on Au. The second peak occurs at about -1.27 V and, to our knowledge, has not previously been reported. Kinetic studies, in which electrochemical desorption curves and XPS spectra were recorded as the total self-assembly time was varied from 1 min to 2 weeks, reveal two distinct adsorption states of thioctic acid on gold surfaces. The first voltammetric wave (-0.93 V) is associated with the desorption of thioctic acid itself, and the second is due to the desorption of oxidized thioctic acid (present as the both the disulfinate and the disulfonate). Finally, oxidized TA was prepared by two synthetic routes and self-assembled monolayers of oxidized TA were allowed to form. Electrochemical desorption experiments showed a single desorption wave at -1.27 V, confirming our assignment.