铁表面自组装缓蚀功能膜的电化学阻抗谱研究

在铁表面自组装十四烷基胺膜.研究该膜在0.5 mol/LH2SO4溶液中对铁的缓蚀性能.电化学阻抗谱测试表明,随着组装时间的延长,缓蚀性能也随之增强,最大缓蚀效率为68.7%.而以十二烷基硫醇和十四烷基胺修饰的混合膜则更为致密、稳定,对铁的缓蚀能力也明显优于仅以十二烷基硫醇或十四烷基胺修饰的单一膜,其缓蚀效率可提高至78.2%.     

Amplified DNA Detection Sensitivity Using Streptavidin－Biotinylated Protein Complex： Characterization by Electrochemical Impedance Spectroscopy

Thioi-terminated oligonucleotide was immobilized to gold sur-face by self-assembly method. A novel amplification strategy was introduced for improving the sensitivity of DNA hybridiza-tion using biotin labeled protein-streptavidin network complex. This complex can be formed in a cross-linking network of molecules so that the amplification of the response signal will be realized due to the big molecular size of the complex. It could be proved from the impedance technique that this amplification strategy caused dramatic improvement of the detection sensitivi-ty. These results give significant advances in the generality and sensitivity as it is applied to biosensing.     

Electrochemical Impedance Spectroscopy of 3 MeV Nickel Implanted into Steel

ABSTRACT

Impedance spectroscopy was used to study the corrosion of a nickel implanted steel sample. The dosaye was 5 × 10¹⁵ ions/cm² and the energy of the nickel ions was 3 MeV. The data from a Simple Randies circuit (R_p and C_dl) were used to explain the corrosion changes observed in a NACE National Association of Corrosion Engineers) Brine solution (used to emulate geothermal brine conditions) at pH 2.0 and 25°C in an air saturated solution. Iron concentrations measured by Induction Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) were used to calculate corrosion rates at various time intervals. Impedance spectroscopy^1,2 is an electrochemical technique which can be used to monitor corrosion and to our knowledge it has not been applied to implanted materials.     

电化学交流阻抗技术表征自组装多层膜

采用电化交流阻抗技术对一种新型电极表面修饰的自组装多层膜进行表征,通过阻抗谱分析,得出电荷传递电阻和双电层电容与膜层数的关系,证明该多层膜随数增加具有均匀增长,结构致密等特性.     

Electrochemical Impedance Spectroscopy of Oxide Layers on the Titanium Surface

The method of electrochemical impedance spectroscopy is used to study oxide layers formed at the titanium surface by a variety of methods. The sample’s polarization permitted the isolation, in an impedance spectrum, of the response caused by the capacitance of the space-charge region, which obeys the Mott-Schottky dependence. It is established that the high-frequency portion of an impedance spectrum is defined by morphological peculiarities of the porous portion of coatings. Assumptions, concerning the nature of a time constant, which reveals itself in the region of low frequencies at polarizing biases, are made. Equivalent circuits, intended for modeling impedance spectra, are proposed. The circuits take into consideration the effect of the space-charge region, as well as the peculiarities of the structure and morphology of the oxide film formed at the titanium surface.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 963–971.Original Russian Text Copyright © 2005 by Gnedenkov, Sinebryukhov.     

Electrochemical Impedance Study of Schiff Base by Means of Self-assembled Monolayer

Schiff base and its metal complex have attracted much attention because of their wide applications in biomedicine and their specific character in photochromic field1. Up to now, reports about Schiff base mainly covered its synthesis and structure2,3. To the best of our knowledge, there is no paper dealing with Schiff base using electrochemical impedance spectroscopy technique by forming self-assembled monolayer. The complexation of Schiff base with the transition metal ions has been confir…     

An Impedance Molecularly Imprinted Sensor for the Detection of Bovine Serum Albumin (BSA) Using the Dynamic Electrochemical Impedance Spectroscopy

A molecularly imprinted electrochemical sensor is successfully developed to detect bovine serum albumin (BSA) based on the dynamic electrochemical impedance spectroscopy (DEIS) instead of the traditional impedance spectroscopy. The sensor is prepared using chitosan and pyrrole as modified material and functional monomers, respectively, and the fast and real‐time characterization of molecular imprinting process can be obtained by DEIS. It is indicated that the removal and rebinding processes of BSA are closely related with the DEIS impedance under dynamic conditions, and the direct correlation between the resulting kinetic information and BSA concentrations can be established. As a result, the impedance changing rates in the initial 5 min of BSA adsorption are linear to the BSA concentrations ranging from 0.0001 to 0.01 ng mL^?1 and 0.01 to 1 ng mL^?1 with a detection limit of 5×10^?5 ng mL^?1 (S/N=3). In addition, the detection of BSA by DEIS does not require the system to be in equilibrium. The sensor also shows simplicity, high sensitivity, good stability and acceptable recovery in real samples, indicating its promising prospects in the fast and real‐time detection of proteins.     

电化学阻抗谱法测定固态聚合物电解质的本体电阻

采用电化学阻抗谱法,对阻抗谱中的聚合物电解质本体电阻（Rb）与膜厚（L）的关系和固体聚合物电解质/惰性电极间的界面阻抗随直流电压的变化趋势进行了研究.结果表明,阻抗谱中聚合物电解质本体电阻（Rb）含有一定的阻塞电极/聚合物电解质间的界面阻抗;由于界面双电层电容的变化,在直流电压0.15～3 V范围内,界面阻抗随电压的增大而减小.     

宏观均相多孔电极电化学阻抗谱基础

电化学阻抗谱可用于诊断多孔电极内电荷转移反应,即界面电荷集聚和电荷传导,以及反应物质输运。本文采用复相量方法,在同态假设条件下,重新推演多孔电极阻抗谱模型,厘清传统多孔电极阻抗谱模型中的模糊性表述。(1) 定义多孔电极表征输入参数,包括电极基体电子电导率σ₁ 、电解质离子电导率σ₂、界面电荷传递电导率g_ct、单位面积界面电容C、固相扩散系数D、速度常数k、电极厚度d、特征孔深L_p 和单位体积表面积S_c;(2) 解析阻抗谱特征输出参数,包括场扩散常数K,特征频率ω₀、ω₁、ω₂、ω₃和 ω_max,它们分别相关于界面传导反应、有限场扩散、氧化还原反应、孔内扩散和最小特征孔尺寸,以及分别对应于从传导到扩散和从扩散到饱和的转折频率f_k1 和f_k2;(3) 当参数X和Z同时变化时(X = σ₁和Z = d,S_c,L_p,C,g_ct,D,k),通过阻抗谱特征参数的演变规律,分析了电荷转移反应中X和Ζ参数耦合竞争;(4)为深入分析电荷转移反应中参数X和Z的耦合竞争,引入了分叉频率f_XZ和f_ZX 。f_XZ和f_ZX所处位置可以用于表征参数X和Z影响电荷转移反应的深度和广度。当分叉频率f_XZ和f_ZX不存在时,表明电荷转移反应中参数X和Z在全频率范围内存在耦合竞争。总之,借助于特征频率和分叉频率,本文一方面研究了动力学参数和微观结构参数对多孔电极中电荷转移反应的影响,另一方面分析谱图的变化及其背后的阻抗谱特征演化规律。本文研究结果可为阻抗谱的系统仿真和辨识提供理论基础,可为多孔电极内电荷转移反应的竞争分析提供技术支撑,还可为电化学储能系统的优化设计提供诊断工具。     

碳钢在N-甲基二乙醇胺介质中的电化学阻抗谱研究

应用电化学阻抗谱(EIS)研究碳钢在N-甲基二乙醇胺(MDEA)介质中的腐蚀行为.实验表明,未经预阴极活化处理的碳钢表面存在氧化膜,溶解氧促使它腐蚀速率增大,经活化处理去除氧化膜后则相反.在不含热稳定性盐(HSS)的MDEA溶液中,碳钢的腐蚀性随MDEA浓度的增加呈先上升后下降趋势;而在HSS高含量的溶液中,其腐蚀性则随MDEA浓度的增加而单调下降.在含有HSS模拟溶液中,碳钢的阳极极化EIS随极化电位由低到高分别出现感抗、负阻抗以及Warburg阻抗响应等特征,对应于孔蚀、活化状态向钝化状态过渡以及进入钝化的趋势,腐蚀反应的阴极过程表现为电化学反应和扩散传质混合控制,阳极过程为电化学反应控制.     

A Highly Sensitive Electrochemical Impedance Spectroscopy Immunosensor for Determination of 1‐Pyrenebutyric Acid Based on the Bifunctionality of Nafion/Gold Nanoparticles Composite Electrode

A simple, highly sensitive and label‐free electrochemical impedance spectroscopy (EIS) immunosensor was developed using Nafion and gold nanoparticles (nano‐Au/Nafion) composites for the determination of 1‐pyrenebutyric acid (PBA). Under the optimal conditions, the amount of immobilized antibody was significantly improved on the nano‐Au/Nafion electrode due to the synergistic effect and biocompatibility of Nafion film and gold nanoparticles composites. The results showed that the sensitivity and stability of nano‐Au/Nafion composite electrode for PBA detection were much better than those of nano‐Au modified glassy carbon electrode (nano‐Au/GCE). The plot of increased electron transfer resistances (R_ets) against the logarithm of PBA concentration is linear over the range from 0.1 to 150 ng·mL^?1 with the detection limit of 0.03 ng·mL^?1. The selectivity and accuracy of the proposed EIS immunosensor were evaluated with satisfactory results.     

Characterization of Formation Kinetics of Self-Assembled Thiol Monolayers on Gold by Electrochemical Impedance Spectroscopy

Interest in the properties of organized monolayers has grown enormously in recent years because these monolayers can provide a means to control the interface at a molecular level1. The self-assemblies of alkanethiols and their derivatives were probably the most intensively studied due to their stability, well-packed structure, ease in preparation, and flexibility in designing the tail group2. The adsorption kinetics of thiol monolayer has been studied by using several techniques, including con…     

锂离子电池的电化学阻抗谱分析研究进展

锂离子电池的电化学阻抗谱（EIS）是研究电化学系统最有力的实验方法之一,在过去的20多年中,EIS 被广泛应用于锂离子电池研究和生产领域,包括研究电极界面反应机理和容量衰减机制,测定相关电极过程动力学参数和电池的健康状态、荷电状态以及电池的内阻。本文分析了锂离子电池中电极极化过程包含的3 个基本物理化学过程———电子输运、离子输运和电化学反应过程,探讨了每一基本物理化学过程包含的步骤及其EIS 谱特征,详细论述了与电子输运相关的基本物理化学过程———接触阻抗和感抗产生的机制;介绍了多孔电极理论及其在锂离子电池中的应用,阐述了基于多孔电极理论进行阻抗谱数值模拟的建模原理与方法。 综述了石墨、硅、二元3d 过渡金属氧化物、LiCoO₂、尖晶石LiMn2O4、LiFePO4、尖晶石Li4Ti5O12、过渡金属氟化物材料等电极的典型阻抗谱特征和各时间常数的归属问题。最后讨论了EIS现存的问题及未来的发展方向。     

Evaluation of the Performance of a Mediatorless Microbial Fuel Cell by Electrochemical Impedance Spectroscopy

A mediatorless microbial fuel cell was developed using Escherichia coli bacteria and platinised titanium mesh as electrodes, producing a maximum power density of 627 mW m^?2. The performance characteristics of the fuel cell were evaluated using both electrochemical and optical techniques. Cyclic Voltammetry showed that an anaerobically grown cell suspension of E. coli was electrochemically active, and is consistent with a role for E. coli‐secreted mediators in the functioning of the cell, after the formation of a biofilm on the surface of the electrode. Electrochemical impedance spectroscopy (EIS) data show a variation in the internal resistance during bacterial growth. EIS analysis based on an equivalent circuit revealed that the initial internal resistance of the cell (5.6 MΩ) initially reduces by around 50 % over an 8 hour period; more or less the same time where the fuel cell reaches its maximum potential of 860 mV, whereupon the resistance begins to increase resulting in the corresponding fall in potential; this trend was reversible upon the introduction of further nutrients into the cell.     

Electrochemical Impedance Spectroscopy in the Characterisation and Application of Modified Electrodes for Electrochemical Sensors and Biosensors

Electrochemical impedance spectroscopy is finding increasing use in electrochemical sensors and biosensors, both in their characterisation, including during successive phases of sensor construction, and in application as a quantitative determination technique. Much of the published work continues to make little use of all the information that can be furnished by full physical modelling and analysis of the impedance spectra, and thus does not throw more than a superficial light on the processes occurring. Analysis is often restricted to estimating values of charge transfer resistances without interpretation and ignoring other electrical equivalent circuit components. In this article, the important basics of electrochemical impedance for electrochemical sensors and biosensors are presented, focussing on the necessary electrical circuit elements. This is followed by examples of its use in characterisation and in electroanalytical applications, at the same time demonstrating how fuller use can be made of the information obtained from complete modelling and analysis of the data in the spectra, the values of the circuit components and their physical meaning. The future outlook for electrochemical impedance in the sensing field is discussed.     

钌镧氧化物涂层在NaCl 溶液中的电化学阻抗谱(EIS)研究

测量了钌镧氧化物涂层的电化学阻抗谱(EIS), 结合循环伏安(CV)及扫描电子显微镜形貌分析, 研究了钌镧氧化物涂层阳极在3.5% NaCl 溶液中电化学表面结构及电化学行为. 在非析氯反应区间, 该涂层EIS 数据的最佳拟合等效电路是R_s(R_ctQ_dl), 在析氯反应区间, 其等效电路为R_s(R_fQ_f)(R_ctWQ_dl). 高频段阻抗行为对应涂层的物理阻抗, 低频段对应涂层与溶液界面的电化学反应阻抗. 实验结果表明, 随着La 浓度增加, 氧化膜及双电层的伪电容增大, 且在La 含量30mol%时达到最大值, 与CV实验结果一致, 证明了加入La 能提高RuO₂涂层的电催化活性. 但在析氯反应区间, 涂层氧化膜的导电性在含La 大于30 mol%之后迅速下降, 在低频段产生Warburg 阻抗, 与其表面钝化和特性吸附现象有关,这是导致含La 70 mol%时电催化活性急剧下降的原因.     

直接甲醇燃料电池的交流阻抗谱分析*

由于能够提供比直流测试方法更为丰富的信息,交流阻抗图谱近些年被广泛的用于直接甲醇燃料电池的研究中。同PEMFC相比,直接甲醇燃料电池具有更为复杂的电极体系。本文通过对交流阻抗技术在直接甲醇燃料电池领域应用的几个关键技术问题的分析,并按照阻抗分析过程的具体的实施步骤加以组织,结合具体的应用实例以阐述交流阻抗谱在直接甲醇燃料电池的各个应用方面,包括电池的原位极化分析,反应机理的剖析,材料性能评估等。     

Electrochemical Impedance Spectroscopic Investigation in Detecting 2,4‐dinitrophenylhydrazine Using Catalytic Effect of Copper at Glassy Electrode

This paper reports on the use of electrochemical impedance spectroscopy (EIS) allied to copper (II) for the determination of 2,4‐dinitrophenylhydrazine (DNPH) at glassy carbon electrode (GCE). The experiment measurements were carried out in methanol at a potential of 0.3 V versus Ag/AgCl. The Nyquist plots were modeled with a Randle equivalent circuit, by identifying the charge transfer resistance as the relevant concentration dependent parameter. These measurements show that the impedance spectra of DNPH increased by the formation of non‐electroactive compound produced from specific interaction between DNPH and Cu (II), which will block the electron‐transfer process of the redox probe. Therefore, the proposed methodology offers a detection limit of 4.0×10^?8 mol L^?1. The proposed methodology was satisfactorily applied to determine DNPH in industrial water samples.     

Stainless Steel Electrodes to Determine Biodiesel Content in Petroleum Diesel Fuel by Electrochemical Impedance Spectroscopy

The blending ratio of biodiesel in petroleum diesel has become one of the most important parameters to ensure the quality of diesel/biodiesel blend. This paper presents a fast and simple method based on electrochemical impedance spectroscopy to determine the biodiesel content in diesel fuel. Different from the method reported in the literature, using a pair of two identical screen printed carbon paste electrodes, in the present work we used two electrodes made from 304 stainless steel with dimensions of 0.8×0.3 cm for the EIS measurements. Improved results were obtained in terms of sensitivity, stability of measurements, electrode reuse, and cost. In this procedure the charge transfer resistance is proportionally related to the biodiesel content, which is used to construct a calibration curve for the analysis of biodiesel content. The procedure was validated by an official method, using two samples, being one of them, certified through an official interlaboratory program of the Brazilian government (Interlaboratory Program for Biodiesel of National Agency of Petroleum, Natural Gas and Biofuels (PIB)/ANP). Good results were obtained in terms of recovery (102.6 %‐102.8 %), precision (coefficient of variation lower than 2.3 %), limit of detection (0.24 %) and limit of quantification (0.80 %). These results indicate that this method is sufficiently suitable as an alternative method to the official method for determining biodiesel content in commercial diesel fuel.     

电化学阻抗谱法研究Cu6Sn5合金负极相变过程

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405 mAh•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.