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首页> 外文期刊>International Journal of Electrochemical Science >Kinetics of Dioxygen Reduction on Gold and Glassy Carbon Electrodes in Neutral Media
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Kinetics of Dioxygen Reduction on Gold and Glassy Carbon Electrodes in Neutral Media

机译：中性介质中金和玻璃碳电极上双氧还原的动力学

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The electrochemical reduction of dioxygen (O2) has been studied on bulk gold (Au) and glassy carbon(GC) electrodes in aqueous neutral solution close to blood ionic composition. The mechanism wasfound to involve two successive bielectronic steps with hydrogen peroxide (H2O2) as the reactionintermediate whatever the electrode material used. On Au, O2 and H2O2 were reduced at closepotentials. The determination of the kinetic parameters of O2 electroreduction was thus achieved afterremoving the cathodic current corresponding to H2O2 reduction. Cyclic voltammograms exhibited onecathodic peak whose both current density (jp) and potential (Ep) evolution as a function of potentialscan rate (r) was in accordance with Randles-Sevcik and Nicholson-Shain equations, respectively.Rotating disk electrode (RDE) voltammetry was also performed and the data were analyzed using theKoutecky-Levich relationship. The effective number of electrons (n) was found to be roughlyindependent of the potential and close to n = 2 when removing H2O2 reduction current whereas itgradually increased up to n = 4 while considering the total current. The Tafel slopes allowed thecathodic transfer coefficients () to be calculated in several neutral aqueous electrolytes. Valuesvaried from 0.25 to 0.49 and were systematically higher on Au than on GC electrode. Similar resultswere obtained with Tafel slopes deduced from Butler-Volmer exploitation of the current-potentialcurves.
机译：已经在接近血液离子组成的中性水溶液中研究了块状金（Au）和玻璃碳（GC）电极上双氧（O2）的电化学还原。发现该机理涉及两个连续的双电子步骤，其中无论使用何种电极材料，都以过氧化氢（H2O2）作为反应中间体。在Au上，O2和H2O2在近电势处还原。因此，在去除与H2O2还原相对应的阴极电流后，即可确定O2电还原的动力学参数。循环伏安图显示一个阴极峰，其电流密度（jp）和电势（Ep）随电势扫描速率（r）的变化分别符合Randles-Sevcik和Nicholson-Shain方程。旋转圆盘电极（RDE）伏安法为还进行了分析，并使用Koutecky-Levich关系对数据进行了分析。发现电子的有效数量（n）大致与电势无关，并且在去除H2O2还原电流时接近n = 2，而在考虑总电流时逐渐增加到n = 4。 Tafel斜率允许在几种中性水性电解质中计算阴极传递系数（）。值在0.25到0.49之间变化，在Au上系统地高于在GC电极上。利用从Butler-Volmer利用电流势曲线得出的Tafel斜率获得了类似的结果。

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