Zhang Yiwei, Stirnemann Guillaume, Hynes James T, Laage Damien
PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
Phys Chem Chem Phys. 2020 May 21;22(19):10581-10591. doi: 10.1039/d0cp00359j. Epub 2020 Mar 9.
The reorientation dynamics of water at electrified graphene interfaces was recently shown [J. Phys. Chem. Lett., 2020, 11, 624-631] to exhibit a surprising and strongly asymmetric behavior: positive electrode potentials slow down interfacial water reorientation, while for increasingly negative potentials water dynamics first accelerates before reaching an extremum and then being retarded for larger potentials. Here we use classical molecular dynamics simulations to determine the molecular mechanisms governing water dynamics at electrified interfaces. We show that changes in water reorientation dynamics with electrode potential arise from the electrified interfaces' impacts on water hydrogen-bond jump exchanges, and can be quantitatively described by the extended jump model. Finally, our simulations indicate that no significant dynamical heterogeneity occurs within the water interfacial layer next to the weakly interacting graphene electrode.
最近的研究表明[《物理化学快报》，2020年，11卷，624 - 631页]，在带电石墨烯界面处，水的重新取向动力学表现出令人惊讶且强烈不对称的行为：正电极电位会减缓界面水的重新取向，而对于越来越负的电位，水的动力学首先加速，在达到极值后，对于更大的电位则会受到抑制。在这里，我们使用经典分子动力学模拟来确定控制带电界面处水动力学的分子机制。我们表明，水的重新取向动力学随电极电位的变化源于带电界面对水氢键跳跃交换的影响，并且可以通过扩展跳跃模型进行定量描述。最后，我们的模拟表明，在与弱相互作用的石墨烯电极相邻的水界面层内，不会发生明显的动力学不均匀性。
