Mesoscopic Pitting Oscillation-Induced Periodic Anodic Layer Electrodissolution of Au(111)
Mesoscopic Pitting Oscillation-Induced Periodic Anodic Layer Electrodissolution of Au(111)
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介观点蚀振荡引起的 Au(111) 周期性阳极层电溶解
DOI：
10.1021/acs.jpclett.1c03300
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Gao Qingyu
中科院分区：
文献类型：
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作者：
Pan Changwei;Niu Mingshuang;Cui Ruijun;Li Lianqun;You Xinyu;Sun Xiao;Ji Chen;Epstein Irving R.;Gao Qingyu
采用原位电化学原子力显微镜研究了Au（111）在铜/氨/硫代硫酸盐厌氧非平衡耗散体系中的电溶。在氨水与铜离子一定的初始浓度比下，溶出过程中坑数和平均坑面积自催化增加，而坑深单调增加。该初始浓度比的进一步增大导致坑数和平均坑面积的振荡动力学，而坑深在一个原子和两个原子之间波动。机理分析表明，硫膜的形成与溶解交替产生周期性点蚀，使金逐层溶解。本文提出了一种新的溶解模式，即振荡点蚀过程产生的周期性层溶解模式，以及深度不断增加的点蚀模式，并利用高初始浓度比的氨铜离子来加速消除Au溶解的钝化硫膜。
The electrodissolution of Au(111) in anaerobic cupric/ammonia/thiosulfate solutions, typical of a non-equilibrium dissipative system, was investigated via in situ electrochemical atomic force microscopy. At a specific initial concentration ratio of aqueous ammonia to cupric ions, the pit number and average pit area increase autocatalytically, while the pit depth increases monotonically during dissolution. A further increase in this initial concentration ratio leads to oscillatory dynamics in the pit number and average pit area while the pit depth fluctuates between one and two atoms. Mechanistic analysis indicates that alternation between formation and dissolution of a sulfur film results in periodic pitting, which produces gold dissolution layer by layer. This work presents a new dissolution mode, i.e., periodic layer dissolution generated by oscillatory pitting processes in addition to a pitting mode with a continually increasing depth, and the use of high initial concentration ratios of ammonia to cupric ion to accelerate the elimination of passivating sulfur film for Au dissolution.