共查询到20条相似文献,搜索用时 15 毫秒
1.
Mohammad Mazloum Ardakani Parvaneh Rahimi Hossein Dehghani Payam Ebrahimi Karami Hamid Reza Zare Somayeh Karami 《Electroanalysis》2007,19(21):2258-2263
The preparation and electrocatalytic behavior of glassy carbon electrodes modified with three different cobalt porphyrin complexes were investigated. The electrocatalytic ability of the modified electrodes for the reduction of dioxygen to hydrogen peroxide and water in air‐saturated aqueous solutions was examined by cyclic voltammetry and chronoamperometry techniques. The porphyrin‐adsorbed glassy carbon electrodes possess excellent electrocatalytic abilities for dioxygen reduction with overpotential about 0.5 V lower than that at a plain glassy carbon electrode. The experimental parameters were optimized and the mechanism of the catalytic process was discussed. The possible effects of the electron‐donating properties of groups in the meso‐position of the porphyrin ring were investigated. 相似文献
2.
The preparation and electrochemical properties of a glassy carbon (GC) electrode modified with cobaloxime complex were investigated. The complex of the type [CoIII(DO)(DOH)pn)Cl2] where (DO)(DOH)pn = N2,N2'-propanediylbis-2,3-butanedione-2-imine-3-oxime) was adsorbed irreversibly and strongly on the surface of preanodized glassy carbon electrode. Electrochemical behavior and stability of modified GC electrode were investigated by cyclic voltammetry. The electrocatalytic reduction of dioxygen has been studied using this modified glassy carbon electrode by cyclic voltammetry, chronoamperometry and rotating disk electrode voltammetry as diagnostic techniques. The modified electrode showed excellent eletrocatalytic ability for the reduction of dioxygen to hydrogen peroxide in acetate buffer (pH 4.0) with overpotential 1.0 V lower than the plain glassy carbon electrode. The formal potential for this modified electrode is not shifted to more negative potentials by repeated reduction-oxidation cycles in oxygen-saturated supporting electrolyte solution. The apparent electron transfer rate constant (kS), the transfer coefficent (alpha) and the catalytic rate constant of O2 reduction at a GC modified electrode were determined by cyclic voltammetry and rotating disk electrode voltammetry and were found to be around 2.6 s(-1), 0.33 and 2.25 x 10(4) M(-1) s(-1). Based on the results, a catalytic mechanism is proposed and discussed. 相似文献
3.
A. N. Golikand J. B. Raoof M. Baghayeri M. Asgari L. Irannejad 《Russian Journal of Electrochemistry》2009,45(8):881-886
The catalytic behaviour of glassy carbon electrode modified by 1,2-dihydroxy antraquinone (Alizarin) was investigated. The electrocatalytic ability of modified electrode for the reduction of dioxygen was examined by cyclic voltammetry and rotating disk electrode (RDE) voltammetry techniques. The Alizarin modified glassy carbon electrode possesses excellent electrocatalytic abilities for dioxygen reduction over potential 400 mV lower than at the bare glassy carbon electrode. Hydrodynamic studies were performed to determine the heterogeneous rate constant for the reduction of O2 at the surface of modified electrode. It was determined by Koutecky-Levich plot. The apparent diffusion coefficient of O2 in O2 saturated acidic solutions was estimated by using Levich equation. Studies show the involvement of four electrons in dioxygen reduction at the surface of this modified electrode. 相似文献
4.
采用循环伏安法研究了负载金属配合物MnSALEN(SALEN=N,N-双水杨醛缩乙二胺)的磷铝分子筛APO-5复合催化剂修饰玻碳电极在水溶液中对分子氧的还原反应的电催化行为.结果表明,氧气的还原峰电位随扫描速率的增大负移,Ep~lnv呈线性关系;其还原峰电流随扫描速率的增大而增强,ip~v1/2呈直线关系.这说明分子氧在修饰电极PS/MnSALEN/APO-5/GCE上的还原是扩散控制的.根据Ep~lnv和ip~v1/2的线性关系计算出中性电解质溶液中分子氧在此修饰电极上的还原反应的电子转移数n接近4.即氧气在此修饰电极上被还原为水. 相似文献
5.
Gold–carbon three dimensional film electrode was prepared from oppositely charged conductive particles by layer-by-layer approach. This was done by alternative immersion of indium tin oxide plate into suspension of positive (gold) and negative (carbon) particles. The film formation is confirmed by scanning electron microscopy. The nanoparticulate film is stable and the obtained electrode exhibits catalytic current of dioxygen reduction connected with the presence of gold nanoparticles. After adsorption of bilirubin oxidase similar effect is observed with substantial decrease of overpotential – typical for bioelectrocatalytic reaction. Both catalytic currents are proportional to the number of immersion and withdrawal steps. 相似文献
6.
A reflux-treatment of soluble polyaniline (SPA) in dimethylformamide (DMF) containing CoCl2 yields an active catalyst for dioxygen reduction which can be adsorbed on the electrode surface firmly. The catalytic reduction of dioxygen at the glassy carbon (GC) electrode modified by the catalyst was studied with cyclic voltammetry (CV), rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE). The kinetic process of dioxygen reduction at the modified electrode was analyzed with a new RRDE theory dealing with a nondiffusion-controlled process on ring electrode. The rate constants for each scheme of dioxygen reduction were calculated, showing that only 2-electron reduction to H2O2 was conducted at the modified electrode. The effect of solution acidity on the electrocatalytic behaviour for dioxygen reduction was investigated. A possibility of initiating catalytic activity for dioxygen reduction was explored with ESCA method. 相似文献
7.
Nafion- and clay-coated electrodes are prepared by casting a known amount of Nafion and clay solutions on the glassy carbon
electrode (GC) surface. Subsequently platinum (Pt) particles are deposited on the GC electrodes and on the Nafion- and clay-coated
GC electrodes. The formation of Pt particles on the modified electrode surface is analysed by scanning electron microscope,
while cyclic voltammetry provides information on the anodisation of Pt particles deposited on the GC electrodes at >0.5 V(SCE)
leading to the formation of platinum oxide (PtO). The involvement of PtO on the catalysed dioxygen reduction to hydrogen peroxide
is reported. Macrocyclic cobalt(III) complex is also used as the electrocatalyst. The effect of pH on the reduction of PtO
and dioxygen in deaerated and oxygenated solutions is studied to understand the dioxygen reduction processes.
Received: 24 January 1997 / Accepted: 14 April 1997 相似文献
8.
The preparation, electrochemical and catalytic behaviour of glassy carbon electrodes modified by anthra-9,10-quinone, its amino derivatives and dyes were investigated. The stability of the modified electrodes was studied by cyclic voltammetry in acidic and neutral media. The electrocatalytic ability of the modified electrodes for the reduction of dioxygen to hydrogen peroxide was examined by cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The influence of pH on the electrochemical and catalytic behaviour was studied and pH 5.0–8.0 was chosen as the optimum working pH by comparing the shift in oxygen reduction potential. The anthraquinone-adsorbed glassy carbon electrodes possess excellent electrocatalytic abilities for dioxygen reduction with overpotential ranging from 280 to 560 mV lower than that at a plain glassy carbon electrode. Hydrodynamic voltammetric studies were performed to determine the heterogeneous rate constants for the reduction of O2 at the surface of the modified electrodes, mass specific activity of the anthraquinones used and the apparent diffusion coefficient of O2 in buffered aqueous O2-saturated solutions. Studies showed the involvement of two electrons in dioxygen reduction. 相似文献
9.
将金属钴离子引入磷酸铝分子筛APO-5制得CoAPO-5分子筛,再把N,N-双水杨醛缩乙二胺(SALEN)希夫碱通过扩散进入CoAPO-5分子筛孔道并与其中的钴离子配位,形成了CoSALEN配合物,构成CoSALEN/APO-5复合材料.应用物理吸附法,以聚苯乙烯(PS)作粘结剂,将CoSALEN/APO-5涂敷在玻碳电极表面制成修饰电极PS/CoSALEN/APO-5/GCE.循环伏安法(CV)、计时电流法(CA)研究了该修饰电极在不同pH电解质溶液中的电化学行为以及对分子氧的催化还原作用.结果表明,制备的修饰电极能有效地催化分子氧的四电子还原,即氧气被电催化还原为水,据此提出可能的氧还原机理. 相似文献
10.
关于金属卟啉、酞菁等化学修饰电极的研究已有大量工作发表.这类电极很不稳定,例如著名的面-面双钴卟啉修饰电报,虽然能直接催化氧还原为水,但经受不住几次电位扫描就失去催化活性.因此,如何提高稳定性就成为研究这类电极的关键.近年来有人报道,吸附在活性碳上的金属卟啉、酞菁类化合物经热处理,可改善其稳定性。热处理后得到的粉状碳催化剂,由于完全不溶于水及有机溶剂,制备电极非常困难。曾有过用这种 相似文献
11.
The colloidal Au nanoparticles-deoxyribonucleic acid (Au(nano)-DNA) film modified glassy carbon electrode (GCE) has been fabricated and the electrochemical reduction of dioxygen (O(2)) at this modified GCE has been studied in 0.2 mol/L air-saturated acetate buffer (pH=5.2) using cyclic voltammetry (CV), chronocoulometry (CC), linear scan voltammetry (LSV) and rotating disk electrode (RDE) as diagnostic techniques. The modified electrode shows excellent enhancement effect towards the reduction of dioxygen to hydrogen peroxide (H(2)O(2)), and the overpotential is lower than that at bare GCE. A well-defined dioxygen reduction peak appeared at about -0.24 V. Based on experimental results, a reaction mechanism is proposed and discussed. 相似文献
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13.
《Physics and Chemistry of Liquids》2012,50(6):708-722
The redox and interactive behaviour of flavin adenine dinucleotide (FAD) with a ruthenium (Ru)-modified glassy carbon electrode (GCE) was investigated. The electron-transfer kinetics on the Ru-modified GCE gives an apparent electron-transfer coefficient, α app of 0.56, and an apparent heterogeneous electron transfer rate constant, k app of 2.32?s?1, respectively. The cyclic voltammetry (CV) complemented by alternating cyclic voltammetry (ACV) shows reduction of FAD to be a quasi-reversible reaction involving FAD adsorption. The adsorption of FAD on the Ru-modified GCE fits a Langmuir adsorption isotherm. The large apparent negative Gibbs energy of adsorption ΔG ads (?38.2?kJ?mol?1) of FAD onto the Ru-modified GCE confirmed a strong chemical adsorption of FAD on the surface. The deposited Ru islands block surface sites for FAD adsorption and the electron-transfer communication between FAD and the electrode surface does not significantly improve with a deposited Ru monolayer. 相似文献
14.
Jiang X Zhang Z Bai H Qu X Jiang J Wang E Dong S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(5):943-951
Electrochemical redox processes of bovine heart cytochrome c were investigated by in situ UV-vis and CD spectroelectrochemistry at bare glassy carbon electrode (GCE) and single-wall carbon nanotubes (SWNTs) modified glassy carbon electrode (SWNTs/GCE) using a long optical path thin layer cell. The spectra obtained at GCE and SWNTs/GCE reflect electrode surface microstructure-dependent changes in protein conformation during redox transition. Potential-dependent conformational distribution curves of cytochrome c obtained by analysis of in situ circular dichroism (CD) spectra using singular value decomposition least square (SVDLS) method show that SWNTs can retain conformation of cytochrome c. Some parameters of the electrochemical reduction process, i.e. the product of electron transfer coefficient and number of electrons (alpha n = 0.3), apparent formal potential (E0' = 0.04 V), were obtained by double logarithmic analysis and standard heterogeneous electron transfer rate constant k0 was obtained by electrochemistry and double logarithmic analysis, respectively. 相似文献
15.
Wei HZ van de Ven TG Omanovic S Zeng YW 《Langmuir : the ACS journal of surfaces and colloids》2008,24(21):12375-12384
The interactive behavior of flavin adenine dinucleotide (FAD) with a bare glassy carbon electrode (GCE) and a Ru-modified GCE was investigated. The reduction of FAD at a GCE/ruthenium-modified GCE surface is a quasi-reversible, surface-controlled process, and our data implied that the attachment of FAD onto the surface is caused by nonspecific adsorption instead of covalent linkage, in which the adenine ring of FAD adopts a flat orientation on the GCE surface in neutral and dilute solutions in order to maximize the pi-pi stacking with the carbon surface and reorients to a perpendicular orientation as the surface gets more crowded. FAD desorption during the exchange with nicotinamide adenine dinucleotide (NAD+) is one order of magnitude slower than desorption in the absence of NAD+, which indicates a strong interaction between FAD and NAD+. General knowledge of the interactive behavior of NAD+ on a FAD-adsorbed GCE provides useful information for the design of a modified electrode surface for the generation of NADH from NAD+. 相似文献
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17.
Adam Lesniewski Joanna Niedziolka-Jonsson Cecile Rizzi Laurent Gaillon Jerzy Rogalski Marcin Opallo 《Electrochemistry communications》2010,12(1):83-85
Carbon ceramic nanoparticulate film electrode was prepared from negatively charged sulfonated carbon nanoparticles and positively charged silicate submicrometre particles with appended imidazolium groups. They were immobilized on an indium tin oxide surface by layer-by-layer method: alternative immersion into suspension of positive and negative particles. The film formation is confirmed by scanning electron microscopy – after larger number of immersion and withdrawal steps more material is deposited on the electrode substrate. The nanoparticulate film is stable and the obtained electrode exhibits a significant increase of capacitive current and faradaic current corresponding to hydrogen peroxide electroreduction. The effect of the number of immersion and withdrawal steps is strikingly visible on dioxygen bioelectrocatalytic reduction current after adsorption of the enzyme laccase. 相似文献
18.
Abstract
The derivatization of a glassy carbon electrode surface was achieved with and without electrochemical reduction of various diazonium salts in acetonitrile solutions. The surfaces were characterized, before and after their attachment, by cyclic voltammetry and electrochemical impedance spectroscopy to evidence the formation of a coating on the carbon surface. The results were indicative of the presence of substituted phenyl groups on the investigated surface. Also, the effects of diazonium thin films at the surface of a glassy carbon electrode, modification time, and salt concentration on their electrochemical responses in the presence of the Fe(CN)63−/4− probe were investigated. Electrochemical impedance measurements indicated that the kinetics of electron transfer is slowed down when the time and the concentration used to modify the glassy carbon electrode are increased. We therefore modified a glassy carbon surface via its derivatization with and without electrochemical reduction of various diazonium salts in acetonitrile solution. 相似文献19.
利用电聚合法和脉冲沉积技术制备了纳米银/聚多巴胺修饰的玻碳电极. 通过循环伏安法和示差脉冲伏安法研究了该修饰电极上对硝基苯酚的电化学行为; 讨论了扫描速度和支持电解质等条件对对硝基苯酚在修饰电极上催化还原的影响. 结果表明, 对硝基苯酚的示差脉冲峰电流在4×10-5~3×10-4 mol/L范围内呈良好的线性关系. 相似文献