Staining of wool using the reaction products of ABTS oxidation by laccase: synergetic effects of ultrasound and cyclic voltammetry

The effects of ultrasound on 2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonate) enzymatic oxidation by laccase (Trametes villosa) has been studied by means of cyclic voltammetry. The reaction was allowed to proceed in the presence of a piece of wool and the coloration depth of the wool fabric was measured by means of K/S. It was observed that cyclic voltammetry is influenced the dyeing process and higher K/S values were obtained when the cyclic voltammetry was combined with the ultrasonic irradiation. Moreover, the K/S value is the sum of the values obtained when the wool staining is done in just the presence of cyclic voltammetry or in just the presence of ultrasound. The results obtained on the indigo carmine decolourization gives information on the importance of controlling the amount of ABTS(+) formed during the ultrasonication process.     

Ionic liquid enhanced magnesium-based polymer electrolytes for electrical double-layer capacitors

This paper describes the preparation and characterization of poly(vinyl alcohol) (PVA)-added ionic liquid-based ion conductors. The polymer electrolyte is incorporated with magnesium triflate [Mg(CF₃SO₃)₂ or MgTf] as salt and 1-butyl-3-methylimidazolium bromide (BmImBr) as ionic liquid. Differential scanning calorimetry (DSC) is carried out to investigate the glass transition temperature which is used to study the plasticizing effect of the ionic liquid. The highest conducting ionic liquid-based polymer electrolyte is used to fabricate electrical double-layer capacitors (EDLC). The electrochemical potential window is evaluated using linear sweep voltammetry (LSV). The electrochemical capacitance of the EDLC is evaluated through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD). The electrochemical potential window of ionic liquid-added polymer electrolyte is extended from 1.35 to 2.6 V. Cyclic voltammetry (CV) proves the improvement in specific capacitance of the electrical double-layer capacitors (EDLCs) containing ionic liquid-added polymer electrolyte.     

Hydrothermal synthesis of one-dimensional assemblies of Pt nanoparticles and their sensor application for simultaneous determination of dopamine and ascorbic acid

One-dimensional assemblies of Pt nanoparticles (NPs) with the size range of 10–20 nm have been synthesized via a simple hydrothermal route using soluble starch as both template and reducing agent. The formation mechanism of the product was studied in details. The electrochemical behavior of dopamine (DA) and ascorbic acid (AA) on the prepared one-dimensionally assembled Pt NPs modified glassy carbon electrode were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques and showed satisfactory results for the simultaneous determination of DA and AA by resolving the overlapping voltammetric responses of DA and AA into two voltammetric peaks.

     

Cyclic voltammograms for H on Pt(111) and Pt(100) from first principles

Cyclic voltammetry is a fundamental experimental method for characterizing electrochemical surfaces. Despite its wide use, a way to quantitatively and directly relate cyclic voltammetry to ab initio calculations has been lacking. We derive the cyclic voltammogram for H on Pt(111) and Pt(100), based solely on density functional theory calculations and standard molecular tables. By relating the gas phase adsorption energy to the electrochemical electrode potential, we provide a direct link between surface science and electrochemistry.     

Chemisorption of a compact polymeric coating on copper surfaces from a benzotriazole solution

Cyclic voltammetry has been employed to study the electrochemical behavior of benzotriazole adsorbed on copper. The structure of the material adsorbed on copper surfaces was analyzed by X-ray photoelectron spectroscopy. We found that benzotriazole could react with a copper atom at zero oxidation state to form a benzotriazole copper (o) complex when copper was immersed in a benzotriazole solution. A more compact film of bisbenzotriazolato copper(II), which shows better anticorrosion effects for copper, was formed when cyclic voltammetry was applied.     

Ti/Sn（1-x）IrxO2电极制备及电生活性氯特性

通过热分解法制备了Ti/Sn(1-x)IrxO2电极,应用SEM观察了电极的表面形貌,通过线性伏安法、循环伏安法等实验方法测试了电极的电化学性能。实验结果表明,Ti/Sn0.7Ir0.3O2电极具有较好的析氯活性;电解产生的活性氯浓度随电流密度的增加先增加后降低;升高电解温度不利于活性氯的产生。     

Stripping voltammetry of Pb and Cu using a microcantilever electrode

Microfabricated silicon microcantilevers coated with gold on one side have been used as working electrode in a three-electrode electrochemical arrangement. In addition to electrochemical current, cantilever bending has been used as a signal for monitoring electrode reactions on the cantilever surface. The microcantilever bending was measured by an optical beam deflection method as the surface potential was scanned and electrochemical reactions occurred on the surface. The microcantilever bending due to differential surface stress was used to sense Pb and Cu using cyclic voltammetry (CV) and linear sweep stripping voltammetry (LSSV).     

Sulphide based anode material for lithium rechargeable battery

In this study, lead sulphide (PbS) was prepared by the chemical bath deposition technique. The sample was characterized by X-ray diffraction (XRD), Energy Dispersive Analysis of X-rays (EDAX) and cyclic voltammetry. EDAX spectrum shows peaks attributable to lead and sulphur. The EDAX analysis also shows that the prepared sample is stoichiometric. Cyclic voltammetry experiments were recorded at 100 mV·s⁻¹ and 400 mV·s⁻¹ scan rates. Results show that the rate controlling electrochemical reaction is electron transfer. The presence of redox waves shows that the lithium intercalation and deintercalation can occur as a result of lattice expansion in PbS. There were no differences in the PbS XRD data before and after the cyclic voltammetry experiments indicating that the PbS structure is not modified upon lithium ion intercalation and deintercalation in PbS. The discharge characteristics for 35 cycles of the cell using the LiCoO₂/PbS couple is presented indicating the possible development of such materials as anode in lithium ion cells.     

Self-assembled bilayers based on organothiol and organotrimethoxysilane on zinc platform

This study describes the formation of a bilayer system developed on electrodeposited zinc. In a first step, a monolayer of 11-mercapto-1-undecanol is grafted on zinc, optimization of the conditions of elaboration have been performed. In a second step, organotrimethoxysilane have been grafted on the zinc modified with the hydroxyl terminated self-assembled monolayer (SAM) to finalize the bilayer system. X-ray photoelectron spectroscopy (XPS), polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) and contact angle measurements are used to characterize each step of modification. An electrochemical evaluation of the different created systems is carried out by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and scanning vibrating electrode technique (SVET). The impact of the modification of zinc using SAM and self-assembled bilayer (SAB) on the electrochemical activity of the surface is highlighted.     

Preparation and physical/electrochemical characterization of carbon nanotube-chitosan modified pencil graphite electrode

In this work, preparation and characterization of single-walled carbon nanotube-chitosan (SWNT-chitosan) modified disposable pencil graphite electrode (PGE) was carried out. Firstly, commercial single-walled carbon nanotube was purified and characterized using thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX) for this purpose. Purified SWNT was mixed with chitosan polymer for preparing their composite. Then, PGE was modified with this composite. The characterization of the modified electrode was carried out using atomic force microscopy (AFM). The electrochemical behaviour of the obtained electrode was investigated and compared with the electrochemical behaviour of chitosan modified and unmodified PGEs using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and alternative current (AC) impedance spectroscopy. In order to obtain more sensitive electrochemical signals, the effect of SWNT concentration was studied. This modified electrode also showed electrocatalytic effect for hydrogen evolution.     

新型对称巯基卟啉及其钴配合物的合成和性质研究

本文用一种新型的方法合成了一种新型卟啉及其钴配合物。用元素分析、紫外-可见、红外、核磁共振等进行了表征。用循环伏安法和差示脉冲法对钴卟啉配合物进行了电化学性质研究。     

新视角审视补偿法测电阻电路

从欧姆定律、伏安法的视角审视各种补偿法测电阻电路,实际上各种补偿法测电阻电路都是和伏安法一样按欧姆定律方式设计的。实践表明按从消除伏安法测电阻电路系统误差逐步推演出完全补偿法的测电阻电路,再讲授补偿法的原理的思路设计教学,收到了很好的效果。     

Investigation of polyaniline films doped with Co2+ as the electrode material for electrochemical supercapacitors

Ionics - H+ and Co2+ ions co-doped polyaniline were synthesized by cyclic voltammetry onto the stainless steel mesh with various concentrations of cobalt chloride (CoCl2 · 6H2O) in...     

硒杂环化合物(4,5-苯并苤硒脑)在金表面上的自组装

为了寻求新的自组装单分子膜体系 ,构建新的功能膜 ,研究了具备平面型的大环共轭硒杂环化合物——— 4,5 苯并苤硒脑 (苯并 [c]硒二唑 ,简称苤硒脑 )在金表面的自组装单分子膜 .通过X射线光电子能谱 (XPS)和电化学手段对其进行表征 .XPS研究结果表明 ,自组装形成单分子膜后 ,苤硒脑分子中Se3d结合能从 5 7.4eV下降到 5 7.1eV ;表明硒杂环化合物是通过金硒键固定在金表面上的 ;电化学循环伏安法实验表明 ,金电极表面上自组装该有机硒后 ,Fe(CN) 63 -/ 4 -的氧化还原峰几乎完全消失 ;以四硼酸钠为底液 ,测得该化合物自组装在金表面上时 ,其还原电位在 - 0 .6 6V ,与在溶液中用裸金电极测得的还原峰电位基本一致 .     

Iron doped vanadium sulfide anemone like nanorod structure for electrochemical water oxidation

Bare and Fe doped vanadium sulfide nanorods was synthesized by employing sol-gel method. The obtained (011) plane revealed and confirmed the orthorhombic phase of vanadium sulfide (VS). Fe doped vanadium sulfide anemone like nanorods structure were demonstrated by morphological evolution employing SEM studies. FTIR studies confirmed the vibrational frequencies of the prepared samples and identify the functional groups. Raman technique is also used to observe the vibrational modes of molecules and PL revealed the prepared samples optical-electronic nature. Additionally, electrochemical studies such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronoampherometry (CA) was recorded for determination of specific capacitance, current density and stability. High doped vanadium sulfide has elevated 1372 F/g specific capacitance at 385 mA/g current density attained from CV and LSV curves at 10 mV/s and it has proven the excellent OER activity.     

Corrosion of graphite in industrial phosphoric acid

The electrochemical corrosion of graphite in industrial phosphoric acid solutions was studied using polarisation curves analysis, cyclic voltammetry, MEB-EDS and secondary ions mass spectroscopy (SIMS). The polarisation curves indicated that graphite has a passive behaviour and the increase of temperature induces an increase of the corrosion rate and the passive current density. The cyclic voltammetry analysis was performed to verify the surface phenomenon of graphite surface and confirmed the role of adsorption oxygen in material corrosion. Spectroscopic analysis (EDS and SIMS) showed that the majority of industrial phosphoric acid impurities were present in the graphite composition indicating that metallic oxides are not the only components of this layer. The presence of these impurities on the graphite induces an increase of corrosion by swelling, exfoliation and cracking.     

An electrochemical sensor based on carbon nanotubes and a new Schiff base for selective determination of dopamine in the presence of uric acid, folic acid, and acetaminophen

In this paper, the electrochemical properties of a carbon paste electrode modified by a synthesized Schiff base, 2,2′-[1,4-phenylenediyl-bis(nitrilomethyl-idene)]-bis(4-hydroxyphenol), and carbon nanotubes were studied by cyclic voltammetry. The modified electrode was used as an electrochemical sensor for catalytic oxidation of dopamine (DA). Differential pulse voltammetry (DPV) of DA by this electrochemical sensor exhibited two linear dynamic ranges with a detection limit (3σ) of 0.42 μM. Also, the selectivity of the prepared electrochemical sensor was checked for determination of DA in the presence of uric acid (UA), folic acid (FA), and acetaminophen (AC). The DPV results indicate that the proposed sensor can be used for simultaneous determination of DA, UA, and FA and also simultaneous determination of DA and AC. Finally, the proposed electrochemical sensor was used for determinations of these substances in real sample.     

基于四苯乙烯基的水杨醛缩芳胺希夫碱化合物的合成及性能研究

将四苯乙烯基与取代水杨醛通过碳氮双键连接起来,合成了基于四苯乙烯基的水杨醛缩芳胺希夫碱TPE-SA1、TPE-SA2、TPE-SA3、TPE-SA4、TPE-SA5。利用IR、NMR、MS和元素分析等对其分子结构进行表征,通过紫外-可见光谱、分子荧光光谱、循环伏安分析法和热重测试分别考察了该类化合物的光学、电化学和热稳定性质。实验结果表明:该类化合物在纯THF溶液中,分别在260 nm和370 nm左右处出现B带和R带紫外吸收峰;在四氢呋喃/水的混合溶液中,表现出典型的聚集诱导发光(AIE)性能。目标化合物的热分解温度分别为262,283,295,278,299℃,具有较好的热稳定性。它们的电离势分别为5.31,5.43,5.41,5.30,5.15eV,电子亲合势均大于4.3 eV。     

最小二乘法在伏安法测电阻实验中的应用

本文介绍了最小二乘法的原理和伏安法测电阻中电流表内接法和外接法的原理,给出了最小二乘法在伏安法测电阻实验数据处理中的应用。     

Electrooxidation of ethanol using Pt rare earth–C electrocatalysts prepared by an alcohol reduction process

Pt rare earth–C electrocatalysts (rare earth = La, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Lu) were prepared by an alcohol reduction process using ethylene glycol as reduction agent and solvent and Vulcan XC 72 as support. The electrocatalysts were characterized by energy-dispersive X-ray analysis, X-ray diffraction (XRD), and cyclic voltammetry. The electrooxidation of ethanol was studied in acid medium by cyclic voltammetry and chronoamperometry using thin porous coating technique. The XRD patterns indicate that all electrocatalysts present the face-centered cubic structure of Pt and the presence of rare earth hydroxides. All electrocatalysts prepared by this methodology showed superior performance for ethanol electrooxidation at room temperature compared to Pt–C.