Differential capacitance of the double layer at the electrode/ionic liquids interface
Differential capacitance of the double layer at the electrode/ionic liquids interface
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DOI：
10.1039/c0cp00170h
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发表时间：
2010-01-01
影响因子：
3.3
通讯作者：
Ralston, John
中科院分区：
文献类型：
--
作者：
Lockett, Vera;Horne, Mike;Ralston, John
用交流阻抗法测量了浸在不同离子液体中的玻碳、铂和金电极的双电层微分电容。讨论了温度、离子液体组成和电极材料对微分电容/电位曲线的影响。对于不同的系统，这些曲线具有不同的整体形状，但都包括几个极端和一个共同的最小值附近的开路电位。我们把这个最小值归因于零电荷电位（PZC）。值得注意的是，如果所施加的电势较大并且远离PZC，则差分电容通常减小。这是由于晶格饱和[A。A. Kornyshev，J. Phys. Chem. B，2007，111，5545]的影响，其导致较厚的双层。随着温度的升高，双电层的微分电容增大，特异性吸附减小。阳离子和阴离子的特异性吸附影响接近PZC的曲线形状。差分电容/电势的一般形状并不强烈地依赖于电极材料的特性。
The differential capacitance of the electrical double layer at glassy carbon, platinum and gold electrodes immersed in various ionic liquids was measured using impedance spectroscopy. We discuss the influence of temperature, the composition of the ionic liquids and the electrode material on the differential capacitance/potential curves. For different systems these curves have various overall shapes, but all include several extremes and a common minimum near the open circuit potential. We attribute this minimum to the potential of zero charge (PZC). Significantly, the differential capacitance generally decreases if the applied potential is large and moving away from the PZC. This is attributed to lattice saturation [A. A. Kornyshev, J. Phys. Chem. B, 2007, 111, 5545] effects which result in a thicker double layer. The differential capacitance of the double layer grows and specific adsorption diminishes with increasing temperature. Specific adsorption of both cations and anions influences the shapes of curves close to the PZC. The general shape of differential capacitance/potential does not depend strongly on the identity of the electrode material.