Suppr超能文献

离子液体中带电界面的水:电吸附的剖析。

Water in ionic liquids at electrified interfaces: the anatomy of electrosorption.

机构信息

State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST) , Wuhan 430074, China.

出版信息

ACS Nano. 2014 Nov 25;8(11):11685-94. doi: 10.1021/nn505017c. Epub 2014 Oct 29.

Abstract

Complete removal of water from room-temperature ionic liquids is nearly impossible. For the electrochemical applications of ionic liquids, how water is distributed in the electrical double layers when the bulk liquids are not perfectly dry can potentially determine whether key advantages of ionic liquids, such as a wide electrochemical window, can be harnessed in practical systems. In this paper, we study the adsorption of water on electrode surfaces in contact with humid, imidazolium-based ionic liquids using molecular dynamics simulations. The results revealed that water molecules tend to accumulate within sub-nanometer distance from charged electrodes. At low amount of water in the bulk, the distributions of ions and of electrostatic potential in the double layer are affected weakly by the presence of water, but the spatial distribution of water molecules is strongly dependent on both. The preferential positions of water molecules in double layers are determined by the balance of several factors: the tendency to follow the positions of the maximal absolute value of the electrical field, the association with their ionic surroundings, and the propensity to settle at positions where more free space is available. The balance between these factors changes with charging the electrode, but the adsorption of water generally increases with voltage. The ion specificity of water electrosorption is manifested in the stronger presence of water near positive electrodes (where anions are the counterions) than near negative electrodes (where cations are counterions). These predictions await experimental verification.

摘要

从室温离子液体中完全去除水几乎是不可能的。对于离子液体的电化学应用,当本体液体不完全干燥时,水在双电层中的分布情况可能会决定离子液体的一些关键优势(如宽电化学窗口)是否能在实际系统中得到利用。在本文中,我们使用分子动力学模拟研究了与潮湿的咪唑基离子液体接触的电极表面上水的吸附。结果表明,水分子倾向于在离带电电极亚纳米距离内聚集。在本体中含水量较低的情况下,双电层中离子和静电势的分布受水的存在影响较弱,但水分子的空间分布强烈依赖于两者。水分子在双电层中的优先位置由几个因素的平衡决定:跟随电场绝对值最大值位置的趋势、与离子环境的缔合以及在有更多自由空间的位置定居的倾向。这些因素之间的平衡随电极充电而变化,但水的吸附通常随电压的增加而增加。水的离子特异性表现在靠近正电极(阴离子为反离子)的地方比靠近负电极(阳离子为反离子)的地方存在更多的水。这些预测有待实验验证。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验