Ir／IrOx金属氧化物电极的H^＋响应行为研究

通过热氧化法制备了铱氧化物电极，研究了电极的各种H^ 响应行为：电极响应开路电位与溶液pH值的线性关系、响应范围、响应速度、滞后效应。分别利用循环伏安法SEM、XPS对铱氧化物电极的内外表面组成、表面形貌与元素价态进行了分析。根据建立的内、外表面电荷积分模型分析了电极H^ 响应速度、滞后效应和氧化膜厚度、形态的关系，提出了水合氧化膜存在下的H^ 响应机理。     

硼酸-硼砂介质中硫离子对不锈钢钝化膜的侵蚀性

 Mott-Schottky图、Nyquist图及阳极极化曲线测定研究了硼酸-硼砂缓冲溶液中硫离子对不锈钢钝化膜耐蚀性能的影响，结果表明：随浸泡时间增加不锈钢电极阻抗值增大，但硫离子加入后阻抗值快速降低；阳极极化曲线测定显示硫离子使不锈钢钝态电流增大；硫离子浓度的增加使不锈钢电极的Mott-Schottky图中体现p-型半导体(铬氧化物)性质的直线段发生较大变化，说明硫离子影响了钝化膜中铬氧化物的性质，使其耐蚀性能降低. 钝化膜      

8-羟基喹啉修饰Fe-W非晶镀层及其耐蚀性

采用电化学方法，研究了8—羟基喹啉修饰Fe—W非晶镀层工艺及其耐蚀性．通过恒压阳极氧化，在Fe—W非晶合金表面形成8—羟基喹啉修饰膜，但膜层耐蚀性较差．在修饰液中加入乙二胺和溶纤剂等助剂，可在电极表面形成一层稳定的彩色修饰膜，铬酸盐封闭处理能增强修饰电极的抗蚀效果．极化曲线测试结果表明，抗蚀层阻滞了氧的阴极还原反应及阳极反应，提高了Fe—W合金镀层在中性NaCl介质中的耐蚀性．     

碳载铂纳米微粒修饰的玻碳电极对甲醇的电催化氧化

利用X射线粉末衍射、透射电镜和扫描电镜对商用Pt/C催化剂反应前后的变化进行了物化表征，同时应用电化学方法研究了甲醇在碳载铂纳米微粒修饰的玻碳电极上的电催化氧化性能。结果表明，修饰电极对甲醇氧化呈现较高的电催化活性。铂氧化物的电化学还原在Pt/c催化剂中受到了抑制，该现象可能是由于Pt与载体碳间的强烈作用所引起的。通过扫描电镜和循环伏安研究表明，该催化剂对甲醇的氧化可能存在着表面结构敏感效应。     

《电镀与精饰》2011年第3期

<正>L半胱氨酸自组装膜对间苯二酚氧化的电催化作用电沉积ZnO薄膜超声处理后结构和缺陷的研究-研究了pH对L-半胱氨酸自组装膜修饰电极的影响,发现该膜对间苯二酚的电化学氧化具有明显的催化作用。在pH=6.86的L-半胱氨酸溶液中制得的膜最致密。在pH=5的醋酸钠-醋酸缓冲溶液中,间苯二酚在L-半胱氨酸自组装膜修饰电极上产生一灵敏的氧化峰,且峰电流与间苯二酚浓度在0.1～0.6mmol/L范围内呈良好的线性关系     

离子选择性酚醛涂层地铜在3%NaCl中电化学行为的影响

利用掺杂离子交换体制备了含不同交换离子品种的阴离子选择性，阳离子选择性和双极性酚醛涂层，研究了涂装不同离子选择性酚醛涂层的铜电极在３％ＮａＣｌ溶液中的腐蚀电化学行为，讨论了各种离子选择性涂层对铜防护性能的差别，并与没有离子选择性的涂层作了比较。     

一种多壁碳纳米管/磷钼酸复合膜修饰电极的制备及其对H2O2的电催化

制备了多壁碳纳米管/磷钼酸复合膜修饰电极,用交流阻抗法对该电极进行了表征,用循环伏安法研究了该修饰电极对过氧化氢的电催化特性,并对其稳定性进行了测定。实验结果表明：电极表面已修饰了致密的碳纳米管磷钼酸膜;在过氧化氢浓度为3.0～13.0 mmol/L范围内,催化电流与过氧化氢的浓度呈现良好的线性关系;修饰电极具有良好的稳定性。     

Al/Al2O3/PPY的制备及其在含氯离子溶液中的阻抗特征

在硝酸和吡咯单体混合溶液中，利用电化学聚合法在铝电极表面合成了聚吡咯(PPY)膜；研究了铝／三氧化二铝／聚吡咯电极在硝酸溶液和氯化钾溶液中的电化学阻抗特征，结果表明，铝电极表面聚吡咯膜的存在，使电极电位正移，加速了铝／三氧化二铝基体在含氯离子溶液中的腐蚀。     

氧化物薄膜促使镍铬合金高温选择氧化的研究

表面沉积Ｙ２Ｏ３薄膜可以促使Ｎｉ－１５％Ｃｒ合金在１０００℃中生成Ｃｒ２Ｏ３选择性氧化膜，氧化量下降约２０倍，而沉积Ａｌ２Ｏ３薄膜仅在较短的时间内使合金的局部表面生成Ｃｒ２Ｏ３选择性氧化膜。从沉积氧化物薄膜对Ｃｒ２Ｏ３氧化膜的生核及生长过程的作用，对氧扩散的阻挡作用，以及氧化物薄膜与Ｃｒ２Ｏ３氧化膜掺杂后引起氧化膜中传质过程和应力状态的变化，分析了氧化物薄膜促使镍铬合金在较低铬含量下发生高温选择氧     

Ag/AgCl氯离子选择性探针电极的制备及其性能表征

将银针在0.1 mol/L HCl电解液中采用恒电流法进行氯化处理,制备Ag/AgCl氯离子选择性电极。采用扫描电镜、能谱与XRD测试,考察氯化前后银表面厚度与表面物质元素的变化;通过对电极对氯离子响应时间的测量,考察电极电位对氯离子的敏感性;通过对响应斜率的测量,考察电极电位与浓度的相关关系。结果表明,在银表面经氯化处理后得物质是AgCl,该电极对氯离子的响应迅速且电位稳定,电极电位与氯离子的浓度呈线性相关关系。制备的选择性电极能在较大的pH值范围内使用,且其他离子对该电极的电位影响较小。     

Anticorrosive properties with catalytic behaviour of primer PANI film and top PPy coating synthesised in presence of novel norephedrine based amino alcohol compound

Polyaniline film as primer coating was deposited on stainless steel (SS) in aniline containing aqueous oxalic acid solution, and subsequent synthesis of top PPy film with 2-((5-ethylthiophen-2-yl) methylamino)-1-phenylpropan-1-ol (AAN) compound of different concentrations was achieved in acetonitrile-LiClO₄ successfully. The corrosion performances of coated and uncoated electrodes in 3·5%NaCl solution were evaluated with the help of AC impedance spectroscopy, anodic polarisation plots and open circuit potential time curves. The protective effect of bilayer coatings with AAN compound on SS electrode grew in parallel with extended exposure time. The regular increase in the charge transfer resistance of SS/PANI/PPy-AAN17 electrode was attributed to allowing the limited ion diffusion of top PPy coating with AAN17 compound. The high 21764 Ω s^?1/2 value of the Warburg coefficient showed that PPy-AAN17 film on the SS/PANI coating led to the formation of protective oxide layers due to the catalytic behaviour of PANI film.     

Surface modification of indium tin oxide films with Au ions implantation: Characterization and application in bioelectrochemistry

Indium tin oxide (ITO) thin film coated glass substrates have been implanted with 21 keV Au ions at a fluence of 1.0 × 10¹⁷ ions/cm² at room temperature. The resulting gold film was characterized with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectra and electrochemical methods. The results reveal that the implanted Au atoms were in the zero-valent metallic state and these Au atoms precipitated to form nanoclusters on the ITO surface whose average radius was estimated between 2 and 5 nm. The preferentially growing orientation was Au (111) plane during the formation process of gold film and the value of gold active surface area normalized by the geometric electrode areas was 0.48 for Au ion implanted ITO (Au/ITO) electrode. The potential utility of Au/ITO films was investigated. The Au/ITO electrode exhibited effective catalytic responses towards biomolecules such as ascorbic acid (AA) oxidation and lowered oxidation potential of AA by 0.6 V when compared with the bare ITO electrode. Myoglobin (Mb) was also successfully immobilized on the Au/ITO electrode and the direct electron transfer between proteins and electrode surface was realized. It was demonstrated that the Au/ITO film offered a favorable microenvironment for the orientation of biomolecules. New biomaterials with specific electrocatalytic and electrochemical features could be fabricated using this method.     

Polyaniline modified electrodes for detection of dyes

Polyaniline (PANI) is one of the most extensively used conjugated polymers in the design of electrochemical sensors. In this study, we report electrochemical dye detection based on PANI for the adsorption of both anionic and cationic dyes from solution. The inherent property of PANI to adsorb dyes has been explored for the development of electrochemical detection of dye in solution. The PANI film was grown on electrode via electrochemical polymerization. The as grown PANI film could easily adsorb the dye in the electrolyte solution and form an insulating layer on the PANI coated electrode. As a result, the current intensity of the PANI film was significantly altered. Furthermore, PANI coated stainless steel (SS) electrodes show a change in the current intensity of Fe²⁺/Fe³⁺ redox peaks due to the addition of dye in electrolyte solution. PANI films coated on both Pt electrodes and non-expensive SS electrodes showed the concentration of dye adsorbed is directly proportional to the current intensity or potential shift and thus can be used for the quantitative detection of textile dyes at very low concentrations.     

Prevention of passive film breakdown on iron by coverage with one-dimensional polymer films of a carboxylate ion self-assembled monolayer modified with alkyltriethoxysilanes

A film composed of a one-dimensional polymer was fabricated by modification of a 16-hydroxyhexadecanoate ion HO(CH₂)₁₅CO₂⁻ self-assembled monolayer (SAM) adsorbed on a passivated iron electrode with octadecyltriethoxysilane C₁₈H₃₇Si(OC₂H₅)₃. The pitting potential, E_pit of the passivated electrode coated with this film was measured by anodic polarization in a borate buffer solution containing 0.1 M of Cl⁻. The E_pit value of the electrode coated with the film was markedly shifted from the value of the bare electrode in the positive direction, indicating prevention of passive film breakdown. No breakdown occurred over the potential range of passive region in some cases. Structure of the modified SAM was discussed by X-ray photoelectron and FTIR reflection spectroscopies and contact angle measurement of the electrode surface covered with the film. Suppression of Cl⁻ accumulation at a defect of the passive film was revealed by electron-probe microanalyses of the surfaces uncoated and coated with the SAM modified with octyltriethoxysilane C₈H₁₇Si(OC₂H₅)₃ after anodic polarization in the borate buffer containing Cl⁻.     

Correlation of interfacial electrode potential and corrosion resistance of plasma polymer coated galvanized steel. Part 1: Ultra-thin plasma polymer films of varying thickness

Ultra-thin SiO₂-like plasma polymer films were deposited on zinc coated steel. Such films led to a strong inhibition of cathodic and anodic electrochemical reactions and a negative shift in the electrode potential. When the SiO₂-like films are additionally coated with a few micron thick organic film, the resulting interface electrode potential is further shifted cathodically down to −0.8 V_SHE as measured by means of a scanning Kelvin probe. This interface potential is about the same as the free corrosion potential of zinc in a chloride containing electrolyte. Accordingly, the interface proved to be extremely resistant to cathodic de-adhesion processes.     

Ultrathin protective films of two-dimensional polymers on passivated iron against corrosion in 0.1 M NaCl

Prevention of iron corrosion in an aerated 0.1 M NaCl solution was investigated by polarization and mass-loss measurements of a passivated iron electrode covered with ultrathin and ordered films of two-dimensional polymers. The films were prepared on the passivated electrode by modification of a 16-hydroxyhexadecanoate ion self-assembled monolayer with 1,2-bis(triethoxysilyl)ethane (C₂H₅O)₃Si(CH₂)₂Si(OC₂H₅)₃ and alkyltriethoxysilane C_nH_{2n + 1}Si(OC₂H₅)₃ (n = 8 or 18). Because crevice corrosion occurred at the initial stage of immersion in the solution preferentially, the edge of electrode covered with the polymer film was coated with epoxy resin. The open-circuit potentials of the covered electrodes in the solution were maintained high, more than −0.2 V/SCE for several hours, indicating that no breakdown of the passive film occurred on the surface. The protective efficiencies of the films were extremely high, more than 99.9% unless the passive film was broken down. The efficiencies after immersion for 24 h almost agreed with those obtained by mass-loss measurements. X-ray photoelectron spectroscopy and electron-probe microanalysis of the passivated surface covered with the polymer film after immersion in the solution for 4 h revealed that pit initiation on the passive film was suppressed by coverage with the polymer film completely.     

Redox active thin films of polymeric metal-free octacyanophthalocyanine

Octacyanophthalocyanine is found to undergo oxidative polymerization under electrochemical conditions at 1.6 V. The polymer was characterized by infrared and UV-Vis spectra. The polymer-coated electrode undergoes a reversible electrochemical process when cycled in various electrolytes. The coated film acts as an ion exchange membrane specific to cations. This was proved by electrochemically trapping Fe(Phen)₃²⁺ ions and monitoring the cyclic voltammetric response of the incorporated cations.     

Ruthenium oxide for effective activation of aluminium sacrificial anodes: a new approach

Abstract

Ruthenium oxide, one of the excellent electrocatalysts having high conductivity and high chemical and thermodynamic stability, has been coated onto the surface of an electrode made from a Al–5 wt-%Zn alloy. The activated aluminium ion was able to diffuse through the porous catalytic hydrophilic layer. Ruthenium oxide coated Al–Zn alloy anodes displayed high open circuit potential and high closed circuit potential during galvanic exposure with mild steel cathodes. A galvanic efficiency as high as 86% with an actual current capacity of 2573 A h kg^-1 was achieved. The RuO₂ film underwent very little deterioration and a considerable mass of the ruthenium oxide film persisted on the anode surface, even after the electrode size had been reduced to one third of its original size owing to galvanic dissolution. These electrodes are economically efficient, as convenient to prepare, install and use as other conventional electrodes, are tolerable of very aggressive media and highly efficient, even under high galvanic current loads.     

Preparation of a two-dimensional polymer film on passivated iron by modification of a carboxylate ion self-assembled monolayer with alkyltriethoxysilanes for preventing passive film breakdown

The effect of an ultrathin, regularly arranged polymer film on prevention of passive film breakdown on iron in the presence of chloride ion was investigated. The film of two-dimensional polymer was prepared by modification of a 16-hydroxyhexadecanoate ion self-assembled monolayer adsorbed on a passivated iron electrode with 1,2-bis(triethoxysilyl)ethane(C₂H₅O)₃Si(CH₂)₂Si(OC₂H₅)₃ and octyltriethoxysilane C₈H₁₇Si(OC₂H₅)₃. The pitting potentials of the passivated electrodes bare and covered with the polymer film were determined by anodic polarization measurements in a borate buffer solution containing 0.1 M of Cl⁻. The pitting potential of the coated electrode was higher than that of the uncoated one, indicating prevention of passive film breakdown. No breakdown was observed over the potential range in the passive and transpassive regions by covering the passive film with the well-arranged two-dimensional polymer film. The film was characterized by X-ray photoelectron and FTIR reflection spectroscopies and measurement of the contact angle with a drop of water.     

Preparation of a one-dimensional polymer film on passivated iron by modification of a carboxylate ion self-assembled monolayer with octyltriethoxysilane for preventing passive film breakdown

A self-assembled monolayer (SAM) of 16-hydroxyhexadecanoate ion HO(CH₂)₁₅CO₂⁻(HOC₁₆A⁻) has been prepared on an iron electrode passivated in a borate buffer solution (pH 8.49) in the preceding paper. In this work, the HOC₁₆A⁻ SAM on the passivated electrode was modified with octyltriethoxysilane C₈H₁₇Si(OC₂H₅)₃ to form a film composed of one-dimensional polymer. Prevention of passive film breakdown was examined by anodic polarization measurements of the electrodes uncoated and coated with the modified SAM in the borate buffer containing 0.1 M of Cl⁻. The pitting potential, E_pit of the coated electrode shifted from that of the uncoated electrode in the positive direction, indicating prevention of passive film breakdown. The anodic current density was decreased in the passive and transpassive regions by coverage with the modified SAM. Neither current spikes nor E_pit was observed in the curve of the passive region in some cases, demonstrating complete protection of the passive film against breakdown in the Cl⁻ solution. The modified SAM on the electrode was characterized by X-ray photoelectron and FTIR reflection spectroscopies and contact angle measurement.