Li Zhujie, Jeanmairet Guillaume, Méndez-Morales Trinidad, Burbano Mario, Haefele Matthieu, Salanne Mathieu
Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Université Paris-Saclay , F-91191 Gif-sur-Yvette, France.
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX , F-75005 Paris, France.
J Phys Chem Lett. 2017 May 4;8(9):1925-1931. doi: 10.1021/acs.jpclett.7b00458. Epub 2017 Apr 17.
Nanoconfinement generally leads to a drastic effect on the physical and chemical properties of ionic liquids. Here we investigate how the electrochemical reactivity in such media may be impacted inside of nanoporous carbon electrodes. To this end, we study a simple electron transfer reaction using molecular dynamics simulations. The electrodes are held at constant electric potential by allowing the atomic charges on the carbon atoms to fluctuate. We show that the Fe/Fe couple dissolved in an ionic liquid exhibits a deviation with respect to Marcus theory. This behavior is rationalized by the stabilization of a solvation state of the Fe cation in the disordered nanoporous electrode that is not observed in the bulk. The simulation results are fitted with a recently proposed two solvation state model, which allows us to estimate the effect of such a deviation on the kinetics of electron transfer inside of nanoporous electrodes.
纳米限域通常会对离子液体的物理和化学性质产生显著影响。在此，我们研究在纳米多孔碳电极内部，此类介质中的电化学反应活性会如何受到影响。为此，我们使用分子动力学模拟研究一个简单的电子转移反应。通过使碳原子上的原子电荷波动，将电极保持在恒定电势。我们表明，溶解在离子液体中的Fe/Fe电对相对于马库斯理论存在偏差。这种行为可通过无序纳米多孔电极中Fe阳离子溶剂化状态的稳定来解释，而在本体中未观察到这种稳定状态。模拟结果与最近提出的双溶剂化状态模型相拟合，这使我们能够估计这种偏差对纳米多孔电极内部电子转移动力学的影响。
