Electrochemical Studies of Electrical Double Layer and Charge Transfer Kinetics at Ag(111) Electrode/Room-Temperature Ionic Liquid Interface

室温离子液体是一类完全由阴、阳离子组成并且在室温或室温附近呈液态的物质，具有宽的电化学窗口、低的蒸汽压以及良好的电导率等传统电解质溶液不可比拟的优势，引起了电化学家的强烈兴趣。然而，相比于离子液体在电沉积、电容器、电催化等体系中的广泛应用，“电极/离子液体”界面双电层和界面电荷转移动力学的研究仍处于初始阶段：界面双电层结构模型和电势分布尚不完善，尤其是现有工作中大量使用的Au单晶电极在离子液体中的表面刻蚀和重构等行为使得界面过程变得更加复杂；而界面电荷转移动力学方面的理论模型严重缺乏，实验研究也多集中于多晶电极上，人们无法对“电极/离子液体”界面双电层结构与界面电荷转移过程建立合理的关联。因此...Ionic liquids are a class of substance, which consist entirely of ionic species and are often fluid at or around room temperature. Compared with traditional electrolyte solutions, ionic liquids have many extraordinary properties, especially the wide electrochemical window, low vapor pressure and good ionic conductivity, which make them of much interest to electrochemists. However, unlike the exten...学位：理学博士院系专业：化学化工学院_物理化学学号：2052011015369

Au(111)/咪唑基离子液体界面结构研究:阳离子侧链长度的影响

本文结合电化学方法与原子力显微镜力曲线技术,研究了两种烷基侧链长度不同的离子液体BMITFSA和OMITFSA在Au(111)电极表面附近的层状结构的数目和耐受力对电位的依赖性,探究了烷基侧链长度变化对界面层状结构的影响.研究表明,不同烷基侧链长度的离子液体体系力-电位曲线形状基本相似.在零电荷电位(the potential of zero charge,PZC)附近时,力值最小,因为此时电极表面荷电量较小,层状结构不稳定;电位偏离PZC的过程中,第一层层状结构力值呈现先增大后减小的趋势.受到烷基侧链所处的不同位置影响,在PZC电位以负,短侧链离子液体的层状结构稳定性较好,而PZC电位以正,长侧链离子液体的稳定性较好.国家自然科学基金项目(No.21673193);;福建省自然科学基金项目(No.2016J01075)资

An STM study on the Structure of Pt(100)/Ionic Liquid OMIPF6 Interface

本文运用电化学扫描隧道显微术研究了离子液体OMIPF6中Pt（100）表面结构在电化学双层区随电极电位的变化. OMI+阳离子在Pt（100）表面形成有序吸附结构，并且在约1.2 V宽的电位区间内稳定地存在Pt（100）表面。在电位负于-0.6 V时，有序吸附结构会发生向无序吸附结构的转变. 在电位正于+0.6 V时，较强的静电排斥力才能克服OMIPF6与Pt（100）表面之间的化学作用，从而导致OMI+阳离子的脱附. 研究表明，OMI+阳离子具有的较长烷基侧链与Pt金属产生的较强化学相互作用是影响该Pt（100）/ OMIPF6界面结构的重要因素.Potential-dependent structures of Pt(100)/ionic liquid 1-methyl-3-octylimidazolium hexafluorophosphate (OMIPF6) interface have been studied by electrochemical scanning tunneling microscopy (ECSTM). The cation OMI+ forms ordered structure on Pt(100) surface, which exists in a potential region of about 1.2 V. When the potential is more negative than -0.6 V, it can be seen that the ordered structure transforms to disordered structure. When the potential shifts positively to +0.6 V, the desorption of cations OMI+ occurs, which indicates that strong electrostatic repulsion is needed to overcome chemical interaction between OMIPF6 and Pt(100) surface, leading to the desorption. The above results demonstrate that owing to the longer alkyl chain OMI+ can interact strongly with Pt(100), which plays an important role in the structure of Pt(100)/ OMIPF6 interface.国家自然科学基金项目（21373174, 21673193）, 福建省自然科学基金项目（2016J01075）资助作者联系地址：厦门大学化学化工学院，固体表面物理化学国家重点实验室，厦门，361005Author's Address: College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005通讯作者E-mail：jwyan@xmu. edu. cn; [email protected]

An Investigation on the Structure of Au(111)/Imidazolium-Based Ionic Liquid Interface: Effect of Alkyl Side Chain Length

本文结合电化学方法与原子力显微镜力曲线技术，研究了两种烷基侧链长度不同的离子液体BMITFSA和OMITFSA在Au(111)电极表面附近的层状结构的数目和耐受力对电位的依赖性，探究了烷基侧链长度变化对界面层状结构的影响. 研究表明，不同烷基侧链长度的离子液体体系力-电位曲线形状基本相似. 在零电荷电位（the potential of zero charge，PZC）附近时，力值最小，因为此时电极表面荷电量较小，层状结构不稳定；电位偏离PZC的过程中，第一层层状结构力值呈现先增大后减小的趋势. 受到烷基侧链所处的不同位置影响，在PZC电位以负，短侧链离子液体的层状结构稳定性较好，而PZC电位以正，长侧链离子液体的稳定性较好.In this work, we comparatively investigated the interfacial structures at Au(111) electrode surfaces in two ionic liquids (ILs) with different alkyl chain lengths by combining AFM force curve technique and electrochemical methods. The number and stability of the layering structures, and their potential-dependency were analyzed. The experimental results indicated that the tendencies of force-potential curves in the two ILs behave the same way. At potentials close to PZC, the ions arrange loosely, which lowers the stability of the layering structure. As the potential shifting away from PZC, more ions attach to electrode surface, which increases the stability of layering structure, while further increase of the ions will weaken the stability because of the lattice saturation of ions. However, the location of the alkyl chain at potentials negative to the PZC differs from that at potentials positive to the PZC, leading to an adverse effect on the stability at negatively charged surface and a synergistic effect on the stability at positively charged surface, respectively.国家自然科学基金项目（No. 21673193）和福建省自然科学基金项目（No. 2016J01075）资助作者联系地址：厦门大学化学化工学院，固体表面物理化学国家重点实验室，福建 厦门 361005Author's Address: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China通讯作者E-mail：[email protected]; [email protected]