INSITU LASER ACTIVATION OF GLASSY-CARBON ELECTRODES
INSITU LASER ACTIVATION OF GLASSY-CARBON ELECTRODES
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DOI：
10.1021/ac00126a036
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发表时间：
1986-11-01
影响因子：
7.4
通讯作者：
MCCREERY, RL
中科院分区：
文献类型：
--
作者：
POON, M;MCCREERY, RL
短脉宽(10 Ns)、高强度(20 mW·cm~(-2))的激光脉冲可使玻碳电极上的非均相电子转移速率提高1-3个数量级。激光脉冲可以直接在感兴趣的溶液中原位输送，如果需要，可以重复输送。铁/亚铁氰化物氧化还原体系的异相电子转移速率常数k在激光作用下从0.004 cm S‘1增加到0.2 cm S’1，从而使该体系在玻碳上的电子转移速率常数k0达到最高。扫描电子显微镜观察到，激光活化导致了表面的微小形态变化，主要是去除了一层明显的碳微粒。这项技术有望成为一种原位重复激活玻璃碳电极的方法，从而避免了通过抛光或其他非原位处理来更新或重新激活的需要。滴汞电极(DME)的广泛使用源于其可再生的表面，每一滴水的可重复的电化学反应，以及没有任何电极历史影响的测量。固体电极被广泛研究，因为它们提供比汞更宽的电位范围，具有更好的机械性能，并且可以对对能量转换、电合成和电分析具有重要作用的反应起到催化作用。然而，人们早就认识到，固体电极的行为与二甲醚的行为不同，它高度依赖于历史，而且其性能可能会被相关溶液中发生的前处理程序或过程极大地改变(1-7)。这些变化表现为非均相电子转移速率的变化，电容或表面法拉第反应的增加，或者在严重的情况下，电极完全失活。它们往往导致不稳定和不可重现的分析性能或完全破坏电催化行为。
Laser pulses of short duration (10 ns) and high Intensity (20 MW cm'2) can Increase the rate of heterogeneous electron transfer at a glassy carbon electrode by 1-3 orders of magnitude. The laser pulse may be delivered in situ, directly in the solution of Interest, repeatedly If desired. The heteroge-neous electron transfer rate constant, k, for the ferrl-/ferrocyanide redox system increases from 0.004 to 0.20 cm s'1 with laser activation, resulting In the highest k0 yet ob-served for this system on glassy carbon. Laser activation results in minor morphological changes to the surface, as observed by scanning electron microscopy, mainly removal of an apparent layer of carbon microparticles. The technique holds promise as a means to repeatedly activate glassy carbon electrodes In situ, thus circumventing the need for renewal or reactivation by polishing or other ex situ treatments.The wide use of the droppingmercury electrode (DME) stems from its renewable surface, a reproducible electrochemical response for each drop, and measurements that are devoid of any electrode history effects. Solid electrodes have been studied extensively because they provide a wider po-tential range than mercury, have better mechanical properties, and can act in a catalytic role for reactions of importance to energy conversion, electrosynthesis, and electroanalysis. However, it has long been recognized that solid electrode behavior, unlikethat of the DME, is highly dependent on history and that performance may be drastically altered by pretreatment procedures or processes occurring in the solution of interest (1-7). These alterations takethe form of changes in heterogeneous electron transfer rate, increases in capaci-tance or surface Faradaic reactions, or in severe cases, total deactivation of the electrode. They often result in unstable and irreproducible analytical performance or complete de-struction of electrocatalytic behavior.