The mechanism of oxygen evolution at superactivated gold electrodes in aqueous alkaline solution
The mechanism of oxygen evolution at superactivated gold electrodes in aqueous alkaline solution
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DOI：
10.1007/s10008-014-2665-y
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发表时间：
2014-12-01
影响因子：
2.5
通讯作者：
Lyons, Michael E. G.
中科院分区：
文献类型：
--
作者：
Doyle, Richard L.;Lyons, Michael E. G.
本文报道了用重复电位循环法研究金的阴极超活化，并讨论了其对析氧反应的意义。的超活化表面表现出瞬态氧析出反应后，单层氧化和广泛的可见氧析出之前。使用各种瞬态和稳态电化学技术的析氧过程的动力学进行了研究。Tafel斜率随金表面活化程度的增加而减小。120，你。48 mV dec（-1），并且对于超活化电极，电荷转移动力学增强超过三个数量级。提出了一种涉及形成Au（OH）（6）（3-）形式的单体Au（III）羟基络合物的机理方案。后者是一个短暂的性质，可以被视为中间体的早期阶段的水合氧化物的增长。这些不稳定物质可通过增强过氧物质的形成来催化氧析出，过氧物质随后分解，同时从表面氧化物损失氧气。这种新的机制路线是在最近的文献研究非常一致，并有可能团结在目前的理解在金表面的析氧反应的一些股。
The cathodic superactivation of gold using a repetitive potential cycling procedure is reported, and its significance for the oxygen evolution reaction is discussed. The superactivated surfaces exhibit a transient oxygen evolution response subsequent to monolayer oxidation and prior to extensive visible oxygen evolution. The kinetics of this oxygen evolution process are studied using a variety of transient and steady-state electrochemical techniques. The Tafel slope is shown to decrease with increased activation of the gold surface from ca. 120 to ca. 48 mV dec(-1), and the charge transfer kinetics are enhanced by over three orders of magnitude for the superactivated electrodes. A mechanistic scheme involving the formation of monomeric Au(III) hydroxyl complexes of the form Au(OH)(6) (3-) is proposed. The latter are of a transient nature and may be regarded as intermediates in the early stages of hydrous -oxide growth. These labile species may catalyse oxygen evolution by enhancing the formation of peroxy species that subsequently decompose with loss of oxygen gas from the surface oxide. This novel mechanistic route is in excellent agreement with recent literature studies and has the potential to unite a number of strands in the current understanding of the oxygen evolution reaction at gold surfaces.