Surface poisoning during electrocatalytic monosaccharide oxidation reactions at gold electrodes in alkaline medium
Surface poisoning during electrocatalytic monosaccharide oxidation reactions at gold electrodes in alkaline medium
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DOI：
10.1016/j.elecom.2007.04.024
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发表时间：
2007-08
影响因子：
5.4
通讯作者：
M. Tominaga;M. Nagashima;Katsuhiko Nishiyama;I. Taniguchi
中科院分区：
文献类型：
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作者：
M. Tominaga;M. Nagashima;Katsuhiko Nishiyama;I. Taniguchi
本文研究了单糖在金电极上电催化氧化反应的表面中毒现象。在循环伏安法研究中，在碱性介质中，观察到己醛糖和戊醛糖型单糖、氨基糖、乙酰氨基葡萄糖和葡萄糖醛酸酰胺在镀金电极上的电催化氧化。然而，在控制电位电解研究中，反应溶液中的电压范围为-0.3至-0.2V，电解过程中的电流随着时间的推移而迅速下降，除非使用葡萄糖胺作为底物。在蒸发的金电极上对葡萄糖在0.1moldm− 3 NaOH中在−0.3V下的电催化氧化进行的表面增强红外吸收（SEIRA）光谱测量和高斯模拟光谱的结果表明，葡萄糖酸作为2电子氧化产物和/或其类似物吸附在金表面上。电化学石英晶体微天平（EQCM）的测量结果，沿着与表面吸附的结果，在金电极上的表面中毒在电解反应过程中，表明，葡萄糖酸和/或其类似物垂直吸附在电极表面上的一个完整的单层包装样构象。在-0.2V下，在0.1moldm-3 NaOH中电氧化葡糖胺的情况下，获得的SEIRA光谱和EQCM结果清楚地表明，作为2-氧化葡糖胺产物的葡糖胺酸没有强烈地结合到金电极表面上。
In the present study, the surface poisoning of electrocatalytic monosaccharide oxidation reactions at gold electrodes were investigated. In the cyclic voltammetric studies, the electrocatalytic oxidation of aldohexose and aldopentose type monosaccharides, aminosugars, acetyl-glucosamine and glucronamide were observed at gold plate electrodes in alkaline medium. However, in controlled-potential electrolytic studies ranging −0.3 to −0.2V in reaction solutions, current flows during electrolyses decreased quickly with time, except when glucosamine was used as a substrate. Results from surface enhanced infrared adsorption (SEIRA) spectroscopic measurements at an evaporated gold electrode for the electrocatalytic oxidation of glucose in 0.1moldm−3NaOH at −0.3V and Gaussian simulated spectra indicated that the gluconic acid as a 2-electron oxidation product and/or its analogs adsorbed onto the gold surface. Electrochemical quartz crystal microbalance (EQCM) measurement results, along with surface adsorption results from surface poisoning at the gold electrode during electrolytic reactions, suggested that gluconic acid and/or its analogs adsorbed vertically onto electrode surfaces in a full monolayer packing-like conformation. In the case of the electro oxidation of glucosamine in 0.1moldm−3NaOH at −0.2V, the obtained SEIRA spectra and EQCM results, clearly indicated that the glucosaminic acid as a 2-oxidation glucosamine product did not strongly bind onto the gold electrode surface.