Alkali Metal Cation Effects in Structuring Pt, Rh, and Au Surfaces through Cathodic Corrosion
Alkali Metal Cation Effects in Structuring Pt, Rh, and Au Surfaces through Cathodic Corrosion
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DOI：
10.1021/acsami.8b13883
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发表时间：
2018-11-14
影响因子：
9.5
通讯作者：
Koper, Marc T. M.
中科院分区：
文献类型：
--
作者：
Hersbach, Thomas J. P.;McCrum, Ian T.;Koper, Marc T. M.
阴极腐蚀是一种电化学蚀刻过程，通过产生纳米颗粒和各种蚀刻特征来改变金属表面。由于这些特征通常具有优先取向，因此可以应用阴极腐蚀来改性和纳米结构化电极表面。然而，阴极腐蚀的这种应用目前受到对其潜在机制的化学理解不足的限制。这包括碱金属阳离子的作用，其被认为在实现阴极腐蚀和控制其最终面偏好方面都是至关重要的。本工作通过实验和理论方法探索Pt、Rh和Au在LiOH、NaOH和KOH中的阴极腐蚀，从而解决了这一知识空白。这些方法表明，阳离子在阴极腐蚀过程中被吸附，并在控制阴极腐蚀的起始电位和最终表面形貌方面发挥主要作用。有趣的是，一个同样重要的作用似乎是由吸附的氢，根据使用文献密度泛函理论数据计算。考虑到氢和电解质阳离子的重要性，假设阴极腐蚀可能通过中间三元金属氢化物进行。这一基本的见解导致了金属特定的建议和更一般的准则，适用于阴极腐蚀结构金属表面。
Cathodic corrosion is an electrochemical etching process that alters metallic surfaces by creating nanoparticles and a variety of etching features. Because these features typically have a preferential orientation, cathodic corrosion can be applied to modify and nanostructure electrode surfaces. However, this application of cathodic corrosion is currently limited by an insufficient chemical understanding of its underlying mechanism. This includes the role of alkali metal cations, which are thought to be crucial in both enabling cathodic corrosion and controlling its final facet preference. This work addresses this knowledge gap by exploring the cathodic corrosion of Pt, Rh, and Au in LiOH, NaOH, and KOH through both experimental and theoretical methods. These methods demonstrate that cations are adsorbed during cathodic corrosion and play a major role in controlling the onset potential and final surface morphology in cathodic corrosion. Interestingly, an equally significant role appears to be played by adsorbed hydrogen, based on calculations using literature density functional theory data. Considering the significance of both hydrogen and electrolyte cations, it is hypothesized that cathodic corrosion might proceed via an intermediate ternary metal hydride. This fundamental insight leads to both metal-specific recommendations and more general guidelines for applying cathodic corrosion to structure metallic surfaces.