离子液体电化学界面特殊双电层结构及电极过程动力学研究

离子液体是一种与传统的分子型溶剂性质完全不同的介质，在电化学中有着广泛应用。电极/离子液体界面具有特殊的双电层结构，必然会显著影响电极反应过程，然而目前文献中缺乏离子液体中电极反应过程与界面结构的关联性研究，难以揭示该界面特殊双电层结构下的电极过程动力学的规律性。本项目拟在前期离子液体电化学界面层状结构研究的基础上，针对该界面特殊双电层结构下的电极过程动力学这一重要的基本科学问题，首先运用原子力显微镜比较研究一系列离子液体在结构明确的单晶电极上的层状结构，并测量层状结构的双电层电势分布；然后运用电化学方法测量离子液体中探针分子的电极过程动力学，研究反应速率常数及其温度依赖性，获得相应的反应活化能；进一步通过与分子型有机溶剂和多晶电极比较，研究不同界面结构的有序性对扩散速率和反应速率常数的影响；最后结合理论模拟揭示电极过程的界面双电层结构依赖性，理解离子液体这一特殊电解液中的电化学基本规律。

The properties of ionic liquids (ILs) are remarkably different from those of conventional molecular solvents, and result in their extensive use in electrochemistry. A consensus is reached that the structure of the electric double layer at electrode/ILs interface is completely different from that at electrode/molecular solvents interface, which will markedly influence the electrode processes. However, the studies about the dependence of the electrode reaction kinetics on the electric double layer structure are still scarcely reported in literature. Based on our previous works about the layering structure in ionic liquids, this project plans to investigate the electrode reaction kinetics in the state of the distinctive structure of the electric double layer in ionic liquids. Firstly, we will employ atomic force microscope to comparatively study the layering structures of a series of ILs on single crystal electrodes including the number of layering, thickness and stability, and measure the potential distribution at the layering structure. Then, electrochemical techniques will be used to study the electrochemical behaviors of probe molecules on single crystal electrodes in ionic liquids, the diffusion coefficients and reaction rate constants can be obtained at different interfaces. Furthermore, we will carry out experiments at variable temperature to demonstrate the dependence of the diffusion coefficient and reaction rate constants on temperature, and calculate the corresponding activation energies. The above results in ionic liquids will be compared with those obtained in organic solvents to elucidate the effect of the layering structure. Finally, the theoretical simulation will be combined with experiments to explore the dependence of the electrode processes on the electric double layer structure. The project benefits understanding the electrochemical characteristics of the special electrolyte.