Non-monotonic Surface Charging Behavior of Platinum: A Paradigm Change
Non-monotonic Surface Charging Behavior of Platinum: A Paradigm Change
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DOI：
10.1021/acs.jpcc.6b03930
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发表时间：
2016-06-30
影响因子：
3.7
通讯作者：
Eikerling, Michael H.
中科院分区：
文献类型：
--
作者：
Huang, Jun;Malek, Ali;Eikerling, Michael H.
在电化学系统中，金属表面充电现象决定了带电电极和溶液中离子之间静电相互作用的强度。一般来说，这些效应对于电化学反应至关重要。历史上，金属的零电荷电势 (pzc) 已被用来参数化表面充电关系。本文提出的带电界面的结构模型超越了过于简化的 pzc 概念，考虑了表面氧化物的形成和界面水分子的取向排序。该模型的解析解揭示了一种特殊的非单调充电行为。由于表面氧化物偶极子，Pt 表面在低电位区域呈现负有效电荷，在中间电位区域呈现正电荷，在高电位区域呈现负电荷。这种非单调行为与 Frumkin 和 Petrii [Electrochim. Acta 1975, 20, 347-359] 迄今为止仍然无法解释。
In electrochemical systems, metal surface charging phenomena dictate the strength of electrostatic interactions between the electrified electrode and ions in solution. These effects are of vital importance for electrochemical reactions in general. Historically, the potential of zero charge (pzc) of the metal has been employed to parametrize the surface charging relation. The structural model of the electrified interface presented in this article goes beyond the oversimplified pzc concept by accounting for the formation of surface oxide and the orientational ordering of interfacial water molecules. The analytical solution of the model reveals a peculiar non-monotonic charging behavior. The Pt surface exhibits a negative effective charge in a low potential region, a positive charge in an intermediate potential region, and a negative charge in a high potential region due to surface oxide dipoles. This non-monotonic behavior is in agreement with a seminal experimental work of Frumkin and Petrii [Electrochim. Acta 1975, 20, 347-359] that had remained hitherto unexplained.