用电化学阻抗谱研究提高锆基无铬化学转化膜耐蚀性的方法

采用含1.4%（质量分数）ZRT-955陶化环保处理剂的水溶液（pH=4.5）,在20°C下对Q235钢板表面锆化处理12 min,通过测量所得锆化膜在0.35%（NH4）2SO4+0.05%NaCl的模拟汗液中的电化学阻抗谱（EIS）,探索了烘干温度和缓蚀处理对膜层耐蚀性的影响。确定最佳烘干温度为180°C。采用硅氧烷酮类缓蚀剂对锆基转化膜进行后处理能够有效地提高其防腐性能

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

Electrochemical Impedance Spectroscopy Study on Phase Transformation of Cu6Sn5 Alloy Anode

The Cu-Sn alloy electrode was prepared by a one-step electrodepositing method using rough Cu foil as the substrate, and was determined as the intermetallic composite Of Cu6Sn5 using an X-ray diffraction (XRD) method. The electrode surface morphology was analyzed by scanning electron microscopy (SEM) which displayed "small islands" structure with many nano-particles on it. The first discharge and charge capacities were determined as 461 and 405 mAh.g(-1), respectively. Electrochemical impedance spectra (EIS) indicated that there appeared three arcs in the Nyquist plots respectively representing the impedance of solid electrolyte interphase film, charge transfer and phase transformation in the first lithiation, and their evolutive principles were also investigated

Electrochemical Impedance Spectroscopy Study on Phase Transformation of Cu_6Sn_5 Alloy Anode

以粗糙铜箔为基底,采用一步电沉积法获得Cu-Sn合金,X射线衍射(Xrd)测试结果显示其主要为Cu6Sn5合金相.扫描电子显微镜(SEM)测试结果表明该合金表面由大量“小岛“组成,且每个“小岛“上存在大量纳米合金粒子.充放电测试结果表明,以该合金为锂离子电池负极,其初始放电(嵌锂)和充电(脱锂)容量分别为461和405MAH·g-1.电化学阻抗谱测试结果显示,Cu6Sn5合金电极在阴极极化过程中分别出现了代表固体电解质界面膜(SEI膜)阻抗、电荷传递阻抗和相变阻抗的圆弧,并详细分析了它们的变化规律.The Cu-Sn alloy electrode was prepared by a one-step electrodepositing method using rough Cu foil as the substrate,and was determined as the intermetallic composite of Cu6Sn5 using an X-ray diffraction(XRD) method.The electrode surface morphology was analyzed by scanning electron microscopy(SEM) which displayed "small islands" structure with many nano-particles on it.The first discharge and charge capacities were determined as 461 and 405 mAh·g-1,respectively.Electrochemical impedance spectra(EIS) indicated that there appeared three arcs in the Nyquist plots respectively representing the impedance of solid electrolyte interphase film,charge transfer and phase transformation in the first lithiation,and their evolutive principles were also investigated.国家重点基础研究和发展规划(973)(No.2009CB220102);国家自然科学基金(No.20773102)资助项

Photoelectrocatalytic Property of Titanium Based TiO2 Nanotube Array Electrode

TiO2 nanotube arrays were prepared by the electrochemical anodization on pure Ti surfaces, and their photoelectrochemical activity was examined. The photoelectrocatalytic property of Ti/TiO2 electrode was evaluated by the degradation of phenol aqueous solution and compared with its photocatalytic performance. The results demonstrated that the photoelectrocatalytic degradation rate of phenol solution for Ti/TiO2 electrode was higher than its photocatalytic degradation rate. The highest photoelectrocatalytic level could be achieved when the bias potential of 0.6 V was applied on the Ti/TiO2 electrode. The results of EIS analyses revealed that the surface reaction step was the only rate limiting step either for the photocatalytic process or for the photoelectrocatalytic process. The extra bias potential could decrease the values of the electron-transfer resistance and increase the separation efficiency of photogenerated electron-hole pairs

Photoelectrocatalytic Property of Titanium Based TiO_2 Nanotube Array Electrode

应用电化学阳极氧化法在纯TI基底上制备高度有序的TIO2纳米管阵列,考察了TI/TIO2光阳极的光电化学响应。以苯酚溶液为目标污染物,研究TI/TIO2电极的光电催化性能,并与光催化性能进行比较。结果表明,该电极光电催化性能优于光催化性能,施加0.6V电压时,光电催化性能最好。电化学阻抗谱分析显示,光电催化和光催化降解过程的速控步骤均为表面反应步骤,外加偏压减小了界面电荷转移阻抗,提高了光生载流子的分离效率。TiO2 nanotube arrays were prepared by the electrochemical anodization on pure Ti surfaces,and their photoelectrochemical activity was examined.The photoelectrocatalytic property of Ti/TiO2 electrode was evaluated by the degradation of phenol aqueous solution and compared with its photocatalytic performance.The results demonstrated that the photoelectrocatalytic degradation rate of phenol solution for Ti/TiO2 electrode was higher than its photocatalytic degradation rate.The highest photoelectrocatalytic level could be achieved when the bias potential of 0.6V was applied on the Ti/TiO2 electrode.The results of EIS analyses revealed that the surface reaction step was the only rate limiting step either for the photocatalytic process or for the photoelectrocatalytic process.The extra bias potential could decrease the values of the electron-transfer resistance and increase the separation efficiency of photogenerated electron-hole pairs.福建省自然科学基金(No.U0750015);福建省科技计划重点课题(No.2007H0031);厦门市科技计划(No.3502Z20073004)资助项

聚乙烯吡咯烷酮对模拟混凝土孔隙液中钢筋的缓蚀效应

应用电化学阻抗谱和极化曲线测试技术,结合扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和拉曼(Raman)光谱分析,研究了表面活性剂聚乙烯吡咯烷酮(PVP)作为缓蚀剂对钢筋的缓蚀效应和机理.结果表明,PVP对pH值为11.0,含0.5 mol/L NaCl的模拟混凝土孔隙液中的钢筋具有良好的缓蚀作用,可有效抑制钢筋的腐蚀;PVP浓度变化对钢筋腐蚀行为有显著的影响,当浓度为25 mg/L时,PVP对钢筋的缓蚀效率达到89.1%;PVP通过在钢筋表面形成吸附膜来抑制钢筋的腐蚀.国家自然科学基金(批准号:21573182,51671163,21203158,21621091,21173177)资助~

Electrochemical Impedance Spectroscopic Studies of the First Lithiation of Si/C Composite Electrode

采用球磨法制备了SI/C复合材料,X射线衍射(Xrd)和扫描电子显微镜(SEM)测试结果显示SI/C复合材料中硅保持着良好的晶体结构且均匀的分散于炭黑基体中.充放电测试结果表明SI/C复合材料首次放电容量高达3393 MAH/g,4周之后可逆容量均保持在1000 MAH/g左右,表现出较好的循环性能.电化学阻抗谱测试结果显示,SI/C复合材料电极在首次嵌锂过程中分别出现了代表接触阻抗、固体电解质相界面界面膜(SEI膜)阻抗、电荷传递阻抗和相变阻抗的圆弧,并详细分析了它们的变化规律.The Si/C composite materials were prepared by ball milling method,and characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM).The result displayed that Si in the Si/C com-posite materials still maintained a good crystal structure and uniformly dispersed in carbon black matrix.The first discharge capacity was 3393 mAh/g,and 4 cycles later still retained 1000 mAh/g,showing better charge-discharge cycle performance.Electrochemical impedance spectroscopy test indicated that there ap-peared three semicircles respectively representing the impedance of contact problems,solid electrolyte in-terface film(SEI film),charge transfer and phase transformation in the first lithiation,and their evolutive principles were also investigated.中央高校基本科研业务费专项资金(Nos.2010LKHX03;2010QNB04;2010QNB05);中国矿业大学科技攀登计划(No.ON090237);江苏省普通高校研究生科研创新计划(No.CX10B_153Z)资助项

Electrochemical impedance spectroscopic study of the first delithiation of spinel lithium manganese oxide

The first delithiation of the spinel LiMn2O4 electrode was studied using electrochemical impedance spectroscopy (EIS). Appropriate equivalent circuits were proposed to fit the experimental EIS data. Based on the fitting results, the variation of the capacitance and the resistance of SEI (solid electrolyte interphase) film, the resistance of charge transfer, and the capacitance of double layer along with the increase of polarization potential were quantitatively analyzed. The results demonstrated that the resistance and the thickness of the SEI film formed on the spinel LiMn2O4 electrode were both increased with the increase of polarization potential in the first delithiation of the spinel LiMn2O4 electrode; The charge transfer resistance decreases below 4.15 V and increases above 4.15 V, corresponding to the two-step reversible (de)intercalation of lithium between LiMn2O4 and lambda-MnO2; The double layer capacitance was influenced by both the state of the spinel LiMn2O4 electrode (different polarization potential) and the two-step reversible (de)intercalation of lithium

自组装金团簇电极库仑台阶现象和电化学阻抗谱研究

采用示差脉冲伏安法研究了自组装单层保护金纳米团簇(C8AuMPC)在常温下二氯甲烷溶液中的量子化电容充电效应.研究结果表明,该团簇在-0.8~0.8V电位范围内有4对明显的量子化电容充电峰.同时采用电化学阻抗谱对C8AuMPC修饰金电极体系的界面结构进行了表征,研究结果表明,MPC自组装层存在两个界面,即金电极-MPC层界面和MPC层-溶液界面;这两个界面的界面电容在MPC的零电荷电位(ca.-0.2V)附近均基本保持不变,随着电位正移或负移到一定程度,界面电容发生变化.进一步利用双隧道结金属岛库仑阻塞效应理论讨论了已有报道中对MPC量子化电容充电的理论分析结果,并证明电化学阻抗谱也是研究MPC量子化电容充电效应的有效方法.另外,用示差脉冲伏安法及循环伏安法研究了电活性物种二茂铁对C8AuMPC量子化电容充电的影响,发现溶液中的电活性物种对MPC层-溶液界面的电子传递的贡献可以忽略,表明该界面的电子传递主要发生在纳米粒子之间