Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes
Evaluation of various strategies to formation of pH responsive hydroquinone-terminated films on carbon electrodes
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DOI：
10.1016/j.electacta.2007.08.018
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发表时间：
2007-12-31
影响因子：
6.6
通讯作者：
Daasbjerg, Kim
中科院分区：
文献类型：
--
作者：
Holm, Allan Hjarbaek;Vase, Karina Hojrup;Daasbjerg, Kim
首先使用电化学预氧化处理提供羧酸官能团，然后固定 H(2)Q 前体 n-(2,5-二甲氧基苯基)烷-1-胺（一般结构：H2N-(CH2)(n)-C6H3(OCH3)(2)，n = 1, 2，将氢醌/醌 (H(2)Q/Q) 氧化还原系统束缚在玻璃碳表面。 4、8 和 12)，通过碳二亚胺化学和最终的去甲基化反应。所得表面在水溶液中表现出预期的化学可逆性，形式电位的 pH 敏感位置（类似于 55 mV/pH 单位），并且峰电位分离从 n = 1 的 0.02 V 增加到 n = 12 的 0.21 V。薄膜非常坚固，可以承受长时间的超声处理和相对较大的电位偏移。虽然薄膜遵循多达 4 个亚甲基单元的预期动力学距离依赖性，但电极动力学比较长烷基间隔基的预期更快。我们认为薄膜无序、电极介导效应和粗糙的电极材料可以解释这些明显的不一致。为了进一步了解这种效应，采用了两种互补的电极修饰策略，从而在碳上实现更好的薄膜排序；通过 4-氨基苯甲酸的氧化沉积或采用等离子体沉积工艺来固定酸类似物来固定苯甲酸薄层。通过电化学方法、原子力显微镜和X射线光电子能谱对各种电极进行了分析。 (c) 2007 Elsevier Ltd. 保留所有权利。
The hydroquinone/quinone (H(2)Q/Q) redox system was tethered to glassy carbon surfaces using first an electrochemical pre-oxidation treatment to afford carboxylic acid functionalities followed by immobilizing the H(2)Q Precursor, n-(2,5-dimethoxyphenyl)alkan-1-amine (general structure: H2N-(CH2)(n)-C6H3(OCH3)(2), n = 1, 2, 4, 8, and 12), by carbodiimide chemistry and a final demethylation reaction. The resultant surfaces exhibited the expected chemical reversibility in aqueous solution with a pH-sensitive position of the formal potential (similar to 55 mV/pH unit), and an increase in the peak potential separation going from 0.02 V for n = 1 to 0.21 V for n = 12. The films were very robust and could withstand prolonged sonication and relatively large potential excursions. While the films followed the expected kinetic distance dependence for up to 4 methylene units the electrode kinetics was faster than expected for longer alkyl spacers. We suggest that film disorder, electrode-mediating effects, and a roughened electrode material could account for these apparent inconsistencies. To further understand such effects, two complementary electrode modification strategies leading to better film ordering on carbon were adapted; immobilizing a thin layer of benzoic acid by oxidative deposition of 4-aminobenzoic acid or employing a plasma deposition process to tether an acid analogue. Analysis of the various electrodes was accomplished by electrochemical methods, atomic force microscopy, and X-ray photoelectron spectroscopy. (c) 2007 Elsevier Ltd. All rights reserved.