Double layer of a gold electrode probed by AFM force measurements
Double layer of a gold electrode probed by AFM force measurements
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DOI：
10.1021/la0117092
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发表时间：
2003-02-18
期刊：
影响因子：
3.9
通讯作者：
Stuart, MAC
中科院分区：
文献类型：
--
作者：
Barten, D;Kleijn, JM;Stuart, MAC
利用胶体探针原子力显微镜研究了金电极与球形二氧化硅探针之间的双电层相互作用。金/溶液界面的双层性质通过电解质的pH值和盐浓度以及通过外部施加电势而变化。金表面的双层电势psi（d）通过根据DLVO（Derjaguin-Landau-Verwey-Overbeek）理论拟合力-距离曲线获得，使用先前获得的二氧化硅探针的双层电势值作为输入参数。发现金电极结合了可逆和可极化界面的特征;即，其电荷和电势由溶液pH和外部电势两者决定。的pH值的依赖性是由于质子吸附和解吸从金表面上的氧化基团。在所研究的电位范围内，psi（d）随外加电位线性变化; psi（d）的变化约为外加电位的10%。零力的电势（psi（d）= 0时的外部电势）随pH而变化。金/电解质界面的各种特征由双功能双层模型很好地描述。本研究的结果形成的基础上的解释金的吸附研究作为pH值和外部施加的电位的函数。
Colloidal probe atomic force microscopy was used to determine the electric double layer interactions between a gold electrode and a spherical silica probe. The double layer properties of the gold/solution interface were varied through the pH and salt concentration of the electrolyte, as well as by externally applying an electric potential. The double layer potentials psi(d) of the gold surface were obtained by fitting the force-distance curves according to the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory, using earlier obtained values for the double layer potential of the silica probe as input parameter. It was found that the gold electrode combines the features of reversible and polarizable interfaces; i.e., its charge and potential are determined by both the solution pH and the external potential. The pH dependence is attributed to proton adsorption and desorption from oxidic groups on the gold surface. In the potential range studied, psi(d) varies linearly with the applied potential; the variation in psi(d) is roughly 10% of that in the applied potential. The potential of zero force (the external potential at which psi(d) = 0) varies with pH. The various features of the gold/electrolyte interface are described well by an amphifunctional double layer model. The results of this study form the basis of the interpretation of adsorption studies on gold as a function of pH and externally applied potential.