Mamme Mesfin Haile, Moors Samuel L C, Mernissi Cherigui El Amine, Terryn Herman, Deconinck Johan, Ustarroz Jon, De Proft Frank
Vrije Universiteit Brussel (VUB), Research Group Electrochemical and Surface Engineering (SURF) Pleinlaan 2 1050 Brussels Belgium
Vrije Universiteit Brussel (VUB), Eenheid Algemene Chemie (ALGC) Pleinlaan 2 1050 Brussels Belgium.
Nanoscale Adv. 2019 Jul 4;1(8):2847-2856. doi: 10.1039/c9na00331b. eCollection 2019 Aug 6.
Deep eutectic solvents (DESs) are a new class of solvents with wider potential window than that of water and high electrochemical stability, making them potential candidates for a wide range of electrochemical systems. However, due to the hygroscopic nature of DESs, the presence of latent water is unavoidable. Therefore, understanding the interfacial structure and the electrosorption and distribution of residual water at the electrified interface is of great importance for the use of these solvents in electrochemical systems. Using atomistic molecular dynamics, we explore the electrosorption and distribution of different amounts of water in 1 : 2 choline chloride-urea DES (Reline) at the electrified graphene interface. We found that both the water distribution and the interfacial structure are sensitive to the electrification of the graphene electrode. As a result, it is found that for moderately charged electrodes, water shows a preferential asymmetric adsorption in the vicinity of the positively charged electrode, partly due to strong intermolecular interactions with anions through hydrogen bonds. In contrast, for highly charged electrodes, water adsorbs at both electrodes due to a strongly enhanced external electrostatic interaction between the electrodes and the water dipoles.
深共熔溶剂(DESs)是一类新型溶剂,其电位窗口比水更宽,且具有高电化学稳定性,这使其成为各种电化学系统的潜在候选溶剂。然而,由于DESs具有吸湿性,不可避免地会存在潜在水分。因此,了解带电界面处的界面结构以及残余水的电吸附和分布情况对于在电化学系统中使用这些溶剂至关重要。我们使用原子分子动力学方法,探究了不同水量在带电石墨烯界面处的1:2氯化胆碱-尿素DES(Reline)中的电吸附和分布情况。我们发现,水的分布和界面结构都对石墨烯电极的带电情况敏感。结果发现,对于中等电荷的电极,水在带正电电极附近表现出优先的不对称吸附,部分原因是通过氢键与阴离子发生了强烈的分子间相互作用。相比之下,对于高电荷的电极,由于电极与水偶极之间强烈增强的外部静电相互作用,水在两个电极上都有吸附。