二茂铁衍生物LB膜修饰Pt电极的循环伏安法性能

本文研究了单取代二茂铁酯和双取代亚麻酸二茂铁酯LB膜修饰Pt电极的循环伏安法性能,用修饰电极的循环伏安模型对实验结果进行拟合,计算了在转移压力分别为20,30,40mN·m^-^1下LB膜修饰Pt电极的覆盖度,并分析和讨论了不同转移压力下修饰的二茂铁LB膜的电荷转移中介作用     

二茂铁衍生物L—B膜修饰SnO2电极的性能

用外层单电子快速转移的氧化还原剂二茂铁及其衍生物修饰电极,在电极/溶液界面作为电子传递的中介物,可使电极上进行的慢反应得到加速、起中介催化作用。目前研究较多的是共价键合和高分子膜的修饰,其他方式的修饰报道不多。用能实现分子有序化排列的L-B膜技术进行氧化还原电活性分子的修饰电极还未见报道。我们用L-B膜技术在SnO_2电极上修饰了二茂铁的衍生物-硬脂酸二茂铁酯(FcOCOC_(17)H_(35))双亲化合物,曾研究了修饰膜的电化学可逆行为和稳定性。本文研究硬脂酸二茂铁酯L-B膜修饰的SnO_2电极     

硬脂酸二茂铁酯L-B膜的电化学性能研究

本文研究二茂铁衍生物——硬脂酸二茂铁酯(FcOCOC₁₇H₃₅)L-B膜技术修饰SnO₂电极的循环伏安性能.实验结果用电极表面吸附(修饰)分子的表面活度理论进行计算机拟合和此较,实验数据与理论符合较好.进一步求得修饰分子的标准电极电势和修饰量。结果表明硬脂酸二茂铁酯L-B膜电化学性能稳定,可逆性较好,可以作为快速电荷转移的修饰电极材料。     

电活性分子L-B膜修饰CdSe薄膜电极的光电化学研究

用电活性分子——硬脂酸二茂铁酯L-B膜修饰了薄膜CdSe电极,在单色光650nm光照下用循环伏安法研究修饰的薄膜电极的光电化学性能。研究结果指出经多层L-B膜修饰后,薄膜CdSe电极的,I-V性能和光稳定性都有明显改善。用界面能级关系讨论了硬脂酸二茂铁酯L-B膜在光照的CdSe薄膜/Fe(CN)₆^4-溶液界面起传递电荷的中介作用,加速了界面的电荷转移。     

二茂铁/L-半胱氨酸修饰电极的电化学行为及电催化性能

利用配对试剂将二茂铁酰胺键合在L-半胱氨酸自组装单层膜(SAM)表面, 制成稳定的二茂铁/L-半胱氨酸修饰电极, 该电极在pH 7.0的磷酸盐缓冲液中有一对很好的氧化还原峰. 运用循环伏安法和交流阻抗谱详细研究了修饰电极的电化学行为, 测得电子转移系数为0.66, 表观电极反应速率常数为6.86 s-1. 该修饰电极对肾上腺素有很好的催化作用, 峰电流与肾上腺素浓度在2.0×10-7～1.0×10-5 mol·dm-3范围内呈现良好的线性关系.     

二茂铁不同取代基对其电化学行为的影响

基于二茂铁不同取代基的氧化还原性,利用玻碳电极研究二茂铁及其醇类、醛类、羧酸类的电化学性质。通过循环伏安法探讨了取代基诱导效应和共轭效应对二茂铁电化学性质的影响,并用计时安培法测定了上述8种化合物的扩散系数,探讨了取代基与参数的相关性。     

血红素LB膜的电化学行为

采用循环伏安法研究了血红素与脑磷脂混合Y型LB（Langmuir-Blodgett）膜在玻碳电极上的电化学行为，结果表明血红素LB膜有良好的电化学活性，在0．1mol/L KCl溶液中有一对氧化还原峰（－0．42V／－0．30V）；将血红素LB膜转移到玻碳电极表面得到的血红素LB膜修饰电极（heme LB-GC）对溶液中溶解氧的电化学还原有良好的催化作用，其催化还原过程具有不可逆电荷传递特性。     

纳米银自组装电极的制备及对高氯酸二茂铁的电化学响应

采用自组装的方法制备了纳米银粒子修饰金电极,并运用循环伏安法、交流阻抗谱探讨了该电极的电化学特性.研究了高氯酸二茂铁在该修饰电极上的直接电化学行为.实验结果表明,高氯酸二茂铁在该修饰电极上具有良好的电流响应.用示差脉冲法测定高氯酸二茂铁,其氧化峰电流与浓度在4.0×10-6～5.0×10-4 mol/L范围呈良好线性关系,线性方程为:Ip(μA)=0.0236c(μmol/L)-0.0975,线性相关系数为0.9982,检出限为2.3×10-7 mol/L(信噪比为3).     

一种结构新颖的二茂铁硫醇自组装膜的电化学行为

合成二茂铁乙烯基吡啶硫醇(FcC2′PyC4SH,I)及其还原产物二茂铁乙烷基吡啶硫醇(FcC2′PyC4SH,Ⅱ).再利用分子自组装技术在金电极表面形成二茂铁乙烯基吡啶硫醇单分子膜,通过循环伏安法探讨了这种自组装膜与结构相关的电化学响应.     

二硫键桥联双二茂铁芳胺的合成及电化学性质研究

以p、m-二茂铁苯胺和p-乙酰硫基苯甲醛反应,合成了两个含p-乙酰硫苯基的二茂铁席夫碱化合物,硼氢化钠还原碳氮双键的同时对乙酰硫基脱保护,得到了两个二硫键桥联双二茂铁芳胺化合物。用熔点,红外光谱,核磁共振氢谱和高分辨质谱对相关化合物进行了结构表征。电化学循环伏安研究表明,p、m-二茂铁苯胺所形成的席夫碱及其还原脱保护产物的循环伏安性质略有差异,其中仲氨基和二茂铁处于对位的二硫键桥联双二茂铁芳胺容易失去电子。电化学研究表明,通过二硫键的均裂和Au-S键可将含刚性芳香环的二茂铁分子通过自组装的方法修饰在金电极表面,可作为潜在的生物化学传感器。     

长链香豆素LB膜对n-Si/Ni液结上的光致电荷转移的影响

本文研究了由硬脂酸香豆素制得的LB膜对n-Si/Ni电极性能的修饰作用.该LB膜沉积方式是Z型的,成膜之后吸收蓝移(由343nm移至325nm).在60mW·cm^-2溴钨灯光照下,n-Si/Ni/3LB/Fe(CN) /Pt电池的光电转换效率增大了一倍,稳定性亦有明显改善.交流阻抗测量表明,光照使n-Si/Ni/3LB电极的电解电阻大大减小,实验结果表明,硬脂酸香豆素LB膜对n-Si/Ni电极上的光致电荷传递过程的修饰作用是良好的.     

Preconcentration and electroanalysis of silver at pt electrode modified with poly(2-aminothiazole)

Conducting poly(2-aminothiazole) (PAT) films were electrodeposited on a platinum disc electrode surface by constant potential electrolysis of 2-aminothiazole (AT) for the stripping voltammetric determination of Ag(I). Ag(I) was preconcentrated on the polymer matrix by dipping the modified Pt electrode (PAT-Pt electrode) into Ag(I)(aq) solution. Effects of the film thickness, reduction potential, pH, preconcentration time, Ag(I) concentration and the interference of some other metal ions on the oxidation peak current of silver were studied. Cu(II) interference observed to be significant for the stripping voltammetric determination of Ag(I). The detection limit was calculated on the basis of signal to noise ratio of 3 as 2 × 10^?7 mol L^?1.     

纳米铂微粒修饰电极上甲醛电催化氧化的电位振荡和电流振荡

通过阴极还原-阳极氧化法制备了钛基纳米铂微粒修饰电极, 扫描电镜观察发现, 分布于钛基体表面的氧化钛膜三维网状孔道中的纳米铂微粒具有高度分散状态. 采用多种电化学手段在该电极上不仅观察到甲醛在恒电流条件下产生的电位振荡, 而且在循环伏安和恒电位两种条件下均观察到强烈的电流振荡, 这进一步证明高度分散的纳米铂微粒使电极的催化活性大大提高, 促进了甲醛及其毒化中间产物的电催化氧化过程, 从而有利于电极上电化学振荡的产生. 研究结果还表明, 甲醛底物浓度、硫酸介质浓度、恒电位或恒电流大小等多种因素对振荡强度、范围或类型会产生规律性的影响.     

New insight into surface properties of LB film of an amphiphilic terpolymer

Amphiphilic terpolymer(TPR) exhibits good film-forming behavior on pure water observed by means ofπ-A isotherms.To gain insight into physical properties of TPR,the films have been deposited on silicon substrates at different surface pressure by Langmuir-Blodgett(LB) technique.It was found that the increase in peak intensities of stretching mode was due to orderly packing of the films.The contact angles increased with increasing surface pressure,indicating an increase in hydrophobicity due to dense packing of chains of TPR.The cyclic voltammetric measurements indicated that TPR showed good current shielding effect for electron-transfer.In a word,LB films of TPR can produce a variety of structures with varied topography,enabling us to control not only the functionality of the surface,but also the interfacial transport characteristics.     

有机钌螯合物/TiO_2杂化膜修饰电极上Pt纳米团簇的光电流增强效应

利用LB膜技术可控制备了纳米单层和多层的二氧化钛-有机钌螯合物杂化膜,并研究了上述无机-有机杂化膜修饰电极在Pt纳米团簇敏化后的光电流增强效应.实验结果表明:(1)纳米单层TiO2/[Ru(phen)2(dC18bpy)]2+(简称为TiO2-Ru)杂化膜的平均厚度为(3.6±0.5)nm;(2)在光照条件下TiO2-Ru杂化膜能有效催化还原[Pt(NH3)6]4+形成粒径位于20～160nm之间的Pt纳米团簇;(3)Pt纳米团簇的引入消除了金属钌螯合物中配体对电子传递的阻碍作用,改变了电子传递途径,从而有效减少了电子空穴对的复合,提高了Pt纳米团簇敏化的n层杂化膜修饰电极(ITO/(TiO2-Ru)n/Pt)在支持电解质中的光电流.与纳米单层TiO2-Ru杂化膜修饰的ITO电极(ITO/TiO2-Ru)相比,当工作电压为900mV时,ITO/TiO2-Ru/Pt在0.1mol·L-1的NaClO4电解质溶液中和光照(λ360nm)条件下,单位面积的光电流提高了约5倍;(4)ITO/(TiO2-Ru)n/Pt电极光电流的大小与杂化膜的层数密切相关,当TiO2-Ru杂化膜的层数从一层、二层增加到四层时,光电流呈现先升高后下降行为,这表明ITO/(TiO2-Ru)n/Pt电极的电子传递过程直接通过非电活性的二氧化钛纳米单层进行.     

Microdimensional Polyaniline: Fabrication and Characterization of Dynamics of Charge Propagation at Microdisk Electrodes

We describe fabrication of microdimensional polyanilne films in a controlled manner by voltammetric potential cycling or controlled potential electrolysis on platinum microdisk electrodes. The film grows in a form of hemispherical microdeposits, and its size largely exceeds the size of a Pt microdisk. Consequently, the film covers both the Pt substrate as well as the surrounding glass seal. Since the adhering polyaniline layer is conducting, the latter situation may lead to an increase in the effective electrode surface area. The lateral growth of polyaniline films outside the microdisk has also been demonstrated by performing diagnostic voltammetric experiments with use of a double microdisk set‐up in which independent polarization of each disk is feasible. Microelectrode‐based chronocoulometry, that involves an uncomplicated well‐defined reduction potential step starting from the emeraldine (conducting) form and ending at leucoemeraldine (nonconducting) form, yields (upon application of a sufficiently short pulse) a well‐defined linear response of charge versus square root of time that is consistent with the linear effective diffusion as the predominant charge propagation mechanism. When describing the system kinetics in terms of the effective (apparent) diffusion coefficient, we expect this parameter to be on the level of 10^?8 cm² s^?1 or lower. The relative changes in dynamics of charge transport are discussed with respect to the polyaniline film loading, the size of microdisk electrode, expansion of the active electrode area, and the choice of electrolyte (strong acid) anion. The results are consistent with the view that when Pt microelectrode is modified with PANI deposit exceeding the size of the microdisk substrate, it behaves in a way as if its surface area is effectively much larger than the geometric area of Pt microdisk.     

Luminescent Langmuir-Blodgett films of platinum(II) complex [Pt(L18)Cl](PF6) (L18 = 2,6-bis(1-octadecylbenzimidazol-2-yl)pyridine)

A novel amphiphilic Pt complex containing 2,6-bis(1-octadecylbenzimidazol-2-yl)pyridine (L18), [Pt(L18)Cl](PF6), has been synthesized. The complex exhibits concentration-dependent absorption and emission spectra in solution. With increasing the concentration of the Pt complex, we observed a new absorption band centered at 550 nm derived from a metal-metal d sigma* to ligand pi* charge transfer (MMLCT) transition and the corresponding broad emission centered at 650 nm. The Pt complex is surface-active, and the surface pressure-area isotherm reveals three phase transitions. The three phases correspond to one liquid-expanding phase and two solid-condensed phases, respectively, with different intermolecular overlap in the "flat-on" orientation at the air-water interface. Without additives such as fatty acids, the complex forms a stable and reproducible Langmuir-Blodgett (LB) multilayer film above a surface pressure of 15 mN m-1. Strong emission from the LB films, even monolayer, was observed. Comparing the relative emission intensity of the MMLCT band for transferred LB monolayer film with that for cast films, we concluded that Pt-Pt interactions are suppressed in the LB film. Instead, the emission at 600 nm arising from the ligand-ligand pi-pi interacted excited state became dominant. The results would provide the insight into the control of molecular ordering for planar Pt complexes from the viewpoint of characteristic excited states.     

The electrode modified with Langmuir–Blodgett film of p-tert-butylcalix[4]arene derivatives with sulfur-containing functionalities for the determination of silver

A new voltammetric sensor, based on a new p-tert-butylcalix[4]arene derivative (TCAD) modified glassy carbon electrode (GCE) using Langmuir–Blodgett (LB) technique, was designed successfully and used for recognition and determination of Ag⁺. The π?-?A isotherms suggested that the monolayer of TCAD can coordinate with Ag⁺ at the air–water surface. Under the optimum experimental conditions, this voltammetric sensor shows a linear voltammetric response for Ag⁺ in the range of 1.0?×?10^?8?～?6.0?×?10^?6?mol?L^?1 with detection limit 5.0?×?10^?9?mol?L^?1. The high sensitivity, selectivity, and stability of this LB film modified electrode also demonstrate its practical application for a simple, rapid and economical determination of Ag⁺ in water sample.     

Electrode Modified with Langmuir–Blodgett (LB) Film of Calixarenes for Preconcentration and Stripping Analysis of Hg(II)

A new type of current sensor, Langmuir–Blodgett (LB) film of calixarene on the surface of glassy carbon electrode (GCE) was prepared for determination of mercury by anodic stripping voltammetry (ASV). An anodic stripping peak was obtained at 0.15 V (vs. SCE) by scanning the potential from ?0.6 to +0.6 V. Compared with a bare GCE, the LB film coated electrode greatly improves the sensitivity of measuring mercury ion. The fabricated electrode in a 0.1 M H₂SO₄+0.01 M HCl solution shows a linear voltammetric response in the range of 0.07–40 μg L^?1 and detection limit of 0.04 μg L^?1 (ca. 2×10^?10 M). The high sensitivity, selectivity, and stability of this LB film modified electrode demonstrates its practical application for a simple, rapid and economical determination of Hg²⁺ in a water sample.