Microwave-enhanced electroanalytical processes: generator-collector voltammetry at paired gold electrode junctions.
Microwave-enhanced electroanalytical processes: generator-collector voltammetry at paired gold electrode junctions.
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微波增强电分析过程：成对金电极连接处的发生器-集电极伏安法。
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
F. Marken
中科院分区：
文献类型：
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作者：
Liza Rassaei;R. W. French;R. Compton;F. Marken
发生器-集电极系统允许监测氧化还原过程和来自多步电极反应的反应中间体。分析上，集电极电流响应是有洞察力的并且高度敏感，这是由于（i）不存在电容电流分量以及（ii）由于发生器和集电极之间的“反馈”而增强的电流响应。在这里，一个对称的金-金结生长的控制电沉积是采用与微波活化的发生器-集电极伏安法。在0.1 M KOH水溶液中研究了三种氧化还原体系：（i）Fe（CN）（6）（3）（-）的还原，（ii）氯霉素的还原，和（iii）氧的还原。当微波辐射聚焦到电极-溶液界面区时，会导致局部温度升高，电极表面温度通常高达380 K（根据两个金电极处Fe（CN）（6）（3）（-/4）（-）平衡电位的变化估计）。所得到的扩散速率的增加和对流的开始导致非线性阿耳忒弥斯极限电流特性和微波功率的收集效率的增加。金电极结几何形状允许扩散效应（其增加差距内的反馈电流）支配对流效应（其抑制反馈电流）。
Generator-collector electrode systems allow redox processes and reaction intermediates from multi-step electrode reactions to be monitored. Analytically, collector electrode current responses are insightful and highly sensitive due to (i) the absence of capacitive current components and (ii) an enhanced current response due to 'feedback' between generator and collector electrode. Here, a symmetric gold-gold junction grown by controlled electro-deposition is employed for generator-collector voltammetry in conjunction with microwave activation. Three redox systems are investigated in aqueous 0.1 M KOH: (i) the reduction of Fe(CN)(6)(3)(-), (ii) the reduction of chloramphenicol, and (iii) the reduction of oxygen. Microwave radiation, when focused into the electrode-solution interfacial zone, causes locally enhanced temperatures with electrode surface temperatures reaching up to typically 380 K (estimated from the shift in the Fe(CN)(6)(3)(-/4)(-) equilibrium potential, at both gold electrodes). The resulting increase in the rate of diffusion and the onset of convection result in non-linear Arrhenius limiting current characteristics and in an increase in collection efficiency with microwave power. The gold electrode junction geometry allows diffusion effects (which increase the feedback current within the gap) to dominate over convection effects (which suppress the feedback current).
DOI：
10.1039/b703986g
发表时间：
2008-06
期刊：
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影响因子：
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作者：
F. Marken
通讯作者：
F. Marken