A polarizable molecular dynamics method for electrode-electrolyte interfacial electron transfer under the constant chemical-potential-difference condition on the electrode electrons
A polarizable molecular dynamics method for electrode-electrolyte interfacial electron transfer under the constant chemical-potential-difference condition on the electrode electrons
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DOI：
10.1063/5.0020619
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发表时间：
2020-08-07
影响因子：
4.4
通讯作者：
Sato, Hirofumi
中科院分区：
文献类型：
--
作者：
Takahashi, Ken;Nakano, Hiroshi;Sato, Hirofumi
电极-电解液界面的电子转移是电化学反应中的关键步骤。计算模拟对于揭示电解质溶液的界面结构和外加电压对能量和动力学的影响起着重要作用。在这种模拟中，重要的是要知道阴极和阳极中电子的化学势，以及界面对体系中电荷分布突然变化的非平衡响应。我们发展了一种经典的全极化分子动力学方法来处理金属电极和溶剂分子都是电子可极化的界面非绝热电子转移过程。根据化学势均衡原理，引入各电极中电子的化学势，使其在阴阳极之间的差值与外加电压相等。研究了溶剂分子的电子极化对电解质溶液界面结构和马库斯自由能曲线的影响。对于准确评估重组能，这些影响是不可忽略的，但随着氧化还原物种靠近电极表面，影响变得不那么明显，在电极表面，金属电极的电子极化起着更主要的作用。
Electron transfer (ET) at an electrode-electrolyte interface is a crucial step in electrochemical reactions. Computational simulations play an important role in unraveling the effects of the interfacial structure of the electrolyte solution and the applied voltage on the energetics and kinetics. In such simulations, it is important to know the chemical potentials of the electrons in the cathode and the anode and the nonequilibrium response of the interface to the abrupt change in the charge distribution in the system. We have developed a classical fully polarizable molecular dynamics method to deal with the interfacial nonadiabatic ET processes in which both the metal electrodes and the solvent molecules are electronically polarizable. The chemical potential of the electrons in each electrode is introduced based on the chemical potential equalization principle, and their difference between the cathode and the anode is kept equal to the applied voltage. We have investigated the effects of the electronic polarization of the solvent molecules on the interfacial structure of the electrolyte solution and the Marcus free energy curves. The effects are non-negligible for the accurate evaluation of the reorganization energies but become less significant as the redox species comes closer to the electrode surface, where the electronic polarization of the metal electrode plays a more dominant role.