Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
Phys Chem Chem Phys. 2010 Oct 21;12(39):12499-512. doi: 10.1039/c0cp00170h. Epub 2010 Aug 19.
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.
使用阻抗谱法测量了浸在各种离子液体中的玻璃碳、铂和金电极的双电层的微分电容。我们讨论了温度、离子液体的组成和电极材料对微分电容/电位曲线的影响。对于不同的体系，这些曲线具有不同的整体形状，但都包括几个极值和一个在开路电位附近的公共最小值。我们将这个最小值归因于零电荷电势（PZC）。值得注意的是，如果施加的电势较大且偏离 PZC，则微分电容通常会减小。这归因于晶格饱和[A. A. Kornyshev, J. Phys. Chem. B, 2007, 111, 5545]效应，导致双电层变厚。随着温度的升高，双电层的微分电容增大，而特定吸附减少。阳离子和阴离子的特定吸附都会影响靠近 PZC 的曲线形状。微分电容/电势的一般形状不太依赖于电极材料的性质。
