共查询到20条相似文献,搜索用时 10 毫秒
1.
2.
《Electroanalysis》2003,15(11):987-990
The electrochemical quartz crystal impedance (EQCI) technique has been applied to investigate glucose oxidation on bare and Ni(OH)2‐modified Au electrodes in 0.2 mol L?1 KOH aqueous solution. The EQCI responses suggest different contributions of H+‐release and OH?‐incorporation reactions of the Ni(OH)2‐film redox process in 0.2 mol L?1 aqueous KOH at different potentials. Glucose adsorption on the Ni(OH)2‐modified Au electrode was studied. A mechanism for potential cyclic redox process of glucose at Ni(OH)2‐modified Au electrode is suggested, mainly based on a comparative EQCI analysis with direct glucose oxidation on bare gold and glucose ad‐/desorption on Ni(OH)2 film. 相似文献
3.
Pt微粒修饰纳米纤维聚苯胺电极对甲醇氧化电催化 总被引:9,自引:0,他引:9
以脉冲电流法制备的纳米纤维状聚苯胺(PANI)为Pt催化剂载体,用它制备了甲醇阳极氧化的催化电极Pt/(nano-fibular PANI).研究结果表明, Pt/(nano-fibular PANI)电极对甲醇氧化具有很好的电催化活性,并有协同催化作用.在相同的Pt载量条件下, Pt/(nano-fibular PANI)电极比Pt微粒修饰的颗粒状聚苯胺电极Pt/(granular PANI)具有更好的电催化活性.此外, Pt的电沉积修饰方法同样影响Pt/(nano-fibular PANI)电极对甲醇氧化的催化活性.脉冲电流法沉积Pt形成的复合电极较循环伏安法电沉积得到的Pt复合电极具有更优异的催化活性. 相似文献
4.
The electrocatalytic activity of platinum for hydrogen oxidation in 0.01 M H2SO4 + 0.1 MNa2SO4 solution has been investigated by scanning electrochemical microscopy (SECM) technique. The cyclic voltammogram (CV), approach curve, area scan imaging and chronoamperometric methods have been used. The results indicate that the imaging capability of the SECM feedback mode can be used more efficiently to visually identify materials' electrocatalytic activity, compared with the approach curve method for identification of the conductive or insulating nature of a surface. The SECM imaging method has demonstrated the effects of Pt substrate potential on the electrocatalytic oxidation of hydrogen under a constant tip potential. It is found that the more positive the Pt substrate potential, the lower the electrocatalytic activity of the Pt. Furthermore, the chronoamperometric results support the variation of the electrocatalytic activity with the Pt substrate potential as well. 相似文献
5.
6.
《Electroanalysis》2006,18(15):1493-1498
Titanium nitride was used as pH‐sensitive material to fabricate all solid‐state pH electrode. The fabrication and the response performance of the pH electrode were described in the paper. The TiN film electrode showed a linear response in the pH range of 2–12 with a near‐Nenstian response (?55 mV/pH). The response time was within 1 min, and the electrode had good reproducibility, stability and low sensitivities for different species. Compared with the glass pH electrode, the electrode exhibited some advantages, for example, without activation, rapid response and high mechanical strength. In addition, the electrode performed excellently in a corrosion medium containing F?(1 M). Electrochemical behaviors of TiN electrode in Britton‐Robinson buffers were studied with Electrochemical Impedance Spectroscopy (EIS). 相似文献
7.
8.
9.
The effects of experimental conditions on the fractal structure of electrosynthetic polyparaphenylene films were studied by electrochemical impedance spectroscopy. The results indicate that, at the potential range (0‐0.6 V), the film surface fractal dimension rises while the corresponding charge transfer resistances Rct decrease as charge increases. This is consistent with the oxidized behavior of the conducting polymer. As for the degradation of electrolytes, scanning electron microscopy observations of poly(para‐pheneylene) (PPP) film provide evidence of the close relationship between the degradation of electrolytes and the film morphology, also in good agreement with the electrochemical impedance results interpretation. The X‐ray photoelectron spectroscopic analysis results present that the relative oxygen content ratio (O/C) of the films increases with the times the electrolyte is used, which reveals that the degradation of the electrolyte may result in a compact and passivation PPP film. 相似文献
10.
11.
聚苯胺膜电极在苯胺单体聚合反应中的电催化性能 总被引:4,自引:0,他引:4
自从第一个导电高聚物掺碘的聚乙炔问世以来[1],人们又陆续开发研制了聚 苯胺(PAn)、聚吡咯和聚噻吩等导电高分子材料. 在众多的导电高分子材料中,聚苯胺以其原 料廉价易得,制备方法简便,导电性能优良,耐高温及抗氧化性能良好等优点而成为最具应用 前景的品种之一. 迄今为止,有关聚苯胺的链结构,掺杂反应,以及导电机理等基础理论方面 的研究已有大量的文献和综述报道[2~6]. 这些基础理论的研究为其应用研究奠定 了坚实的基础. 早在60年代,人们就发现,聚苯胺对氧化亚氮分解及丁二烯异构化反应具有独 特的催化作用;同时,聚苯胺具有超出几何表面的活性表面,故可对某些反应具有选择性的催 化作用. 因此,人们开始研究聚苯胺膜电极对某些电极反应的电催化性能[7~12]. 我国科学工作者在这一领域也做了许多有益的工作,如董绍俊等[13]研究了聚苯胺 膜修饰电极对抗坏血酸的电催化氧化,罗维忠等[14]研究了聚苯胺膜电极对Fe(Ⅱ) 和Sb(Ⅲ)的电催化作用. 本文主要讨论了扫描速度、苯胺单体浓度及温度对聚苯胺膜电极在 苯胺单体聚合过程中电催化性能的影响,为利用聚苯胺处理含苯胺废水提供了一定的理论依 据. 相似文献
12.
13.
《Electroanalysis》2005,17(7):549-555
Carbon film disk electrodes with Nafion coatings have been characterized by electrochemical impedance spectroscopy (EIS) with a view to a better understanding of their advantages and limitations in electroanalysis, particularly in anodic stripping voltammetry of metal ions. After initial examination by cyclic voltammetry, spectra were recorded over the full potential range in acetate buffer solution at the bare electrodes, electrodes electrochemically pretreated in acid solution, and Nafion‐coated pretreated electrodes in the presence and absence of dissolved oxygen. EIS equivalent circuit analysis clearly demonstrated the changes between these electrode assemblies. In order to simulate anodic stripping voltammetry conditions, spectra were also obtained in the presence of cadmium and lead ions in solution at Nafion‐coated electrodes, both after metal ion deposition and following re‐oxidation. Permanent changes to the structure of the Nafion film occurred, which has implications for use of these electrode assemblies in anodic stripping voltammetry at relatively high trace metal ion concentrations. 相似文献
14.
《Electroanalysis》2004,16(3):199-209
Electrocatalytic oxidation of methanol on a glassy carbon disc electrode modified with Ni(II)‐hematoporphyrin IX, complex and conditioned by potential recycling in a limited range (between 100 and 600 mV vs. SCE) in 0.10 M NaOH solution, abbreviated as NiOHPME(A), was studied by cyclic voltammetry in alkaline medium. The results were compared with those obtained for a NiO modified glassy carbon electrode, NiOME, prepared in similar conditions. The findings show that the NiOHP film at NiOHPME(A) behaves as an efficient electrocatalyst for the oxidation of methanol in alkaline medium via Ni(III) species with the cross‐exchange reaction occurring throughout the layer at a low concentration of methanol and for a thin film of modifier. A plausible mechanism was proposed for catalytic oxidation of methanol at NiOHP modified electrode. Moreover, the effects of various parameters such as the scan rate, methanol concentration, thickness of NiOHP film and the real surface area of modified electrode on the oxidation of methanol were investigated. Finally, it has been shown that the NiOHPME(A) has a long‐term stability toward the oxidation of methanol. 相似文献
15.
QiuHongLI LinNIU ChangQiaoZHANG FengHuaWEI HuZHANG 《中国化学快报》2004,15(1):115-117
The oxidation of methanol was investigated on platinum-modified polyaniline electrode.Changes in the electrode rotation rates (Ω) during platinum electrodeposition remarkably affect the formation and distribution of platinum in the polymer matrix and consequently lead to different currents of methanol oxidation. The results show that platinum loading is proportional to rotation rates Ω^1/2. 相似文献
16.
Yang Chiang Ling‐Sheng Jang Sung‐Lin Tsai Ming‐Kun Chen Min‐Haw Wang 《Electroanalysis》2014,26(10):2129-2137
The electrical impedance analysis of single cells can provide information on cells’ pathological condition in various environments. Cell electrical properties are affected by factors such as the location, adhesion, and size of the cell. The proposed microfluidic device captures a single cell, maintains growth conditions, and allows single‐melanoma‐cell impedance to be measured using an impedance analyzer and a function generator. The rate of impedance variation (ROIV) can be used to determine cell growth conditions. Cellular apoptosis affects cell size and membrane surface area, and thus the electrical properties of cells. At 24 h without Antrodia cinnamomea (AC) addition, ROIV was 15.23 %, 17.04 %, and 12.60 % at temperatures of 34 °C, 37 °C, and 40 °C, respectively. At 24 h and 37 °C, ROIV was 17.04 %, 40.37 %, and 45.02 % for AC concentrations of 0, 20, and 40 µL/mL, respectively. The results show that the cell impedance variation of cells cultured without AC is much lower than that of cells cultured with AC. Regarding cellular morphology, with AC addition, the cells shrank obviously after 24 h, whereas they barely shrank without AC addition. 相似文献
17.
LI Dang-guo CHEN Da-rong WANG Jia-dao CHEN Hao-sheng State Key Laboratory of Tribology Tsinghua University Beijing P.R.China 《高等学校化学研究》2011,(4):697-702
The semi-conductive performances of hot growth film on 316L stainless steel were studied by means of electrochemical impedance spectroscopy(EIS) and Mott-Schottky analysis.The chemical compositions of the hot growth films were detected by X-ray photoelectron spectroscopy(XPS).The results show that the transfer resistance and film resistance increase with increasing temperature to 400℃,then they decrease sharply with further continuously increasing temperature.Formation time plays an important role in determ... 相似文献
18.
Electrochemical Detection of Steroid Hormones Using a Nickel‐Modified Glassy Carbon Electrode
下载免费PDF全文
![点击此处可从《Electroanalysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Grace W. Muna Michael Partridge Hala Sirhan Bridget VerVaet Nigel Guerra Holly Garner 《Electroanalysis》2014,26(10):2145-2151
This paper demonstrates the development of an analytical method for detecting steroid hormones by coupling HPLC to electrochemical detection, using a nickel‐modified glassy carbon electrode. The method was evaluated in terms of sensitivity, linear dynamic range, limit of detection, and response stability. The developed method exhibited good figures of merit for the steroid hormones studied with no evidence of electrode fouling. As an example, the limit of detection (S/N=3) for E3 was 0.10 µM and the response precision (n=5) was 0.6 %. The application of the method for the analysis of a real river water sample is demonstrated. 相似文献
19.
《Electroanalysis》2006,18(24):2413-2420
The authors designed an amperometric gas sensor employing a three‐electrode system, with gold working electrode vacuum sublimation deposited directly on Nafion membrane. The paper presents the results of investigations on static characteristics of a sulfur dioxide sensor with the internal electrolytes containing various dimethylsulfoxide/water ratio. Impedance data were analyzed using an electrical equivalent circuit in order to evaluate its particular elements. 相似文献
20.
The electrochemical behavior of oxadiargyl at a graphene‐paste electrode modified with an azo dye, 2‐(4‐((4‐acetylphenyl)diazenyl)phenylamino)ethanol (ADPE), ADPE/MGRPE was investigated. The modified electrode showed high electrocatalytic activity toward oxadiargyl. The apparent electron transfer rate constant (ks) and charge transfer coefficient (α) between electrode and ADPE were 1.16 s?1 and 0.41, respectively. The differential pulse voltammetry response of the modified graphene‐paste electrode was linear against the concentration of oxadiargyl in the range from 0.03 to 1.4 mg L?1. The limit of detection was found to be 1.3 µg L?1 (S/N=3). The practical analytical utility of this electrode was demonstrated by measurement of oxadiargyl in river water, soil and rice samples. 相似文献