ELECTRON-TRANSFER KINETICS OF AQUATED FE+3/+2, EU+3/+2, AND V+3/+2 AT CARBON ELECTRODES - INNER-SPHERE CATALYSIS BY SURFACE OXIDES
ELECTRON-TRANSFER KINETICS OF AQUATED FE+3/+2, EU+3/+2, AND V+3/+2 AT CARBON ELECTRODES - INNER-SPHERE CATALYSIS BY SURFACE OXIDES
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DOI：
10.1149/1.2220868
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发表时间：
1993-09-01
影响因子：
3.9
通讯作者：
MCCREERY, RL
中科院分区：
文献类型：
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作者：
MCDERMOTT, CA;KNETEN, KR;MCCREERY, RL
研究了三种自交换率较低的含水金属离子在碳表面的电子转移动力学。这三种离子在清洁断裂的玻碳(GC)和高度有序的热解石墨(HOPG)的基面上都表现出缓慢的动力学行为。这些反应似乎是外圈反应，其反应速度与根据自身汇率预测的反应速度大致一致。GC或HOPG的电化学氧化极大地增加了电子转移速率常数，使其值明显大于外球反应的预测值。Eu(Aq)+3/+2的增加幅度最大，硅烷化的效果最好。表面氧化物为含水离子在碳处的内部球状催化提供了场所，可能涉及类似于常见配体乙酰丙酮的表面氧化物结构。
The electron-transfer kinetics for three aquated metal ions with low self-exchange-rates were examined on well-characterized carbon surfaces. All three ions exhibited slow kinetics on clean fractured glassy carbon (GC) and on the basal plane of highly ordered pyrolytic graphite (HOPG). The reactions appeared to be outer sphere and had rates approximately consistent with those predicted from the self-exchange rates. Electrochemical oxidation of either GC or HOPG greatly increased the electron-transfer rate constant to values significantly greater than predicted for outer-sphere reactions. The increase was greatest for Eu(aq)+3/+2 and was eliminated if the surf ace was silanized. Surface oxides provide sites for inner-sphere catalysis of the aquated ions at carbon, perhaps involving a surface oxide structure similar to the common ligand acetoacetonate.