物理化学学报 >> 1991, Vol. 7 >> Issue (05): 549-552.doi: 10.3866/PKU.WHXB19910507

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电极/溶液界面单分子吸附层的统计力学处理 IV. 水溶液中银单晶电极的内层微分电容

苏文煅; 周绍民; 周小林   

  1. 厦门大学化学系，厦门 361005；厦门大学计算中心
  • 收稿日期:1990-04-16 修回日期:1990-11-21 发布日期:1991-10-15
  • 通讯作者: 苏文煅

Statistical Mechanical Treatment of Adsorbed Monolayer at Electrode Solution Interface IV. The Inner Layer Differential Capacity of Silver Single Crystal Electrode in Aqueous Solution

Su Wen-Duan; Zhou Shao-Min; Zhou Xiao-Lin   

  1. Department of Chemistry, Xiamen Univeristy, Xiamen 361005; Computer Center, Xiamen University
  • Received:1990-04-16 Revised:1990-11-21 Published:1991-10-15
  • Contact: Su Wen-Duan

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摘要： 根据本文系列I~[6]提出的电极/溶液界面溶剂化层偶极取向分布模型, 拟合计算Ag(111)、Ag(100)及Ag(110)/水溶液界面的内层微分电容(C_1)～表面电荷密度(σ)变化关系。表明在银电极上, 吸附水分子似分别稳定在金属原子点阵的顶位(111)或穴位(100)及(110)。讨论了溶剂化层的结构与性质对C_1～σ曲线可能产生的影响。

关键词: 电极/溶液界面, 双电层, 内层微分电容, Ag(单晶)/水溶液体系

Abstract: Based on the model of dipole orientation distribution presented in previous paper, the monolayer adsorption isotherm for solvent molecules at the interface of solid me- tal electrode wsa derived. The dependence of inner-layer differential capacity(C_1) on the surface charge density(σ) was estimated by curve-fitting for Ag(111), Ag(100) and Ag(110)/aqueous solution interface. The calculated results are shown. In analyzing the fitting parameters obtained from this treatment, it was found that the water molecules would preferentially be strongly adsorped on the top sites of (111)-plane, but would be on the hollow site at (110)-or(100)-plane. The high values of the inner-layer differential capacity for silver single crystal electrodes were interpreted in terms of those effects, i.e., the thickness of adsorption monolayer was diminished due to water molecules stably adsorbed on the hollow site of crystal face, and the influence of the interaction between metal and water molecules or between dipole-dipole of adsorbed molecules on the variation of potential drop acrossed the inner-layer with the surface charge at electrode.

Key words: Electrode/Solution interface, Electrical double layer, Inner layer differential capacity, Ag(single crystal)/aqueous system