Chemistry Commons^™

Passivation Behaviors Of Mo, W Electrodes In Mgcl2-Kcl-Nacl-Cacl2 Molten Salt For Electrolysis Of Magnesium, Ye Chen, Ke Ye

Journal of Electrochemistry

The discharge process and passivation behaviors of Mg(Ⅱ) on cathode(Mo, W) in MgCl₂-KCl-NaCl-CaCl₂ molten salt system had been investigated by means of cyclic voltammetry and chronoamperometry. The composition of molten salt was MgCl(10%) + CaCl(20%) + NaCl(60%) + KCl(10%)(by mass) and the temperature of electrolysis was 725 ℃. The deposition potential of Mo was 37 mV more negative than that of W, while the peak current was sharper than Mo according to the voltammograms at 0.05 V/s, indicating that the passivation on Mo cathode is easier than W. The formation of MgO impurities during the electrolysis could …

The Effect Of Annealed Temperature On Properties Of Ru-Ir-Sn Oxide Anode Coatings, Lei Ji, Jun-Tao Wang, Li-Kun Xu, Wen-Bin Liu, Gui-Lin Xue

Journal of Electrochemistry

The anode coatings of Ru-Ir-Sn oxide were prepared by sol-gel method with different annealed temperatures.The influences of annealed temperature in properties of anode coatings were characterized by scanning electron microscope(SEM),energy dispersive X-ray detector(EDX),X-ray diffraction(XRD),potential of chlorine evolution,accelerated life,cyclic voltammetry and electrochemical impedance spectroscopy(EIS) tests.The results showed that the annealed temperature affected the morphology of coatings,while the electric quantities of cyclic voltammetry and double layer capacitances of anode coatings had a tendency to fall down and the potential of chlorine evolution and accelerated life had a tendency to increase as the annealed temperature increased.

Preparation And Photoelectrochemical Properties Of Fe-Doped Tio2 Nanotube Arrays, Jing Li, Lan Sun, Hui-Fang Zhuang, Cheng-Lin Wang, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

The Fe-doped TiO₂ nanotube arrays were fabricated in Fe(NO₃)₃-HF mixing solutions by electrochemical anodic oxidation method,and characterized by FESEM,Raman,XPS and DRS.The effect of Fe concentratiions on photoelectrochemical property of the arrays was also investigated.The diameters and lengths of Fe-doped TiO₂ nanotube arrays were 50~90 nm and about 200 nm,respectively.Compared with the undoped TiO₂ nanotube arrays,the absorption edge of Fe-doped TiO₂ nanotube arrays appeared red shifting.The more Fe content,the larger red shifting,in addition,the photocurrent of Fe-doped TiO₂ nanotube arrays increased obviously.

Cyclic Voltammetry And In Situ Ftir Studies Of Cyanide Adsorption On Nanostructured Au Film Electrode In Alkaline Solutions, Chun-Hua Zhen, Chun-Jie Fan, Shi-Gang Sun

Journal of Electrochemistry

The adsorption of cyanide(CN^-) on electrodes of nanometer scale thin film of gold supported on glassy carbon(nm-Au/GC) in alkaline solutions were investigated using cyclic voltammetry and in situ FTIR spectroscopy.It has revealed that the electrodeposited nanostructured Au thin film exhibited AIREs(abnormal infrared effects) for CN^-adsorption,which manifested 3 nonlinear IR spectral features: inversion of the direction of CN^-band,enhancement of IR absorption of adsorbed CN-species(about 39.2 folds) and increase in the FWHM(full width at half maximum) of CN^-band.

Quick Tester With Usb Interface For The Corrosion Protection Properties Of Organic Coating, Xiang-Dong Zhuo, Chang-Jian Lin

Journal of Electrochemistry

According to the principle of multiple dynamic potential scaning polarization,a quick tester with USB interface for the fast study of corrosion resistance properties of organic coating/ metal system has been developed.This tester is portable,facile,practical,and has a strong function for data collection and data treatment.It is not only suitable for the accelerated test in laboratory,but also for the quick test and evaluation to the corrosion resistance of the organic coating/metal system in industrial spots.

Cu Doping Lifepo4 And Its Electrochemical Performance, Ming-Sen Zheng, Shan-Ke Liu, Shi-Gang Sun, Quan-Feng Dong

Journal of Electrochemistry

LiFePO₄ and LiFePO₄ doped with Cu²⁺ ions were synthesized by solid-state reactions.The structure of LiFePO₄ and the Fe valence were analyzed by the XRD(X-ray diffraction) and XPS(X-ray photoelectron spectroscopy) respectively.The Cu doping position in LiFePO₄ is discussed.It has found that the volume of LiFePO₄ by doping Cu²⁺ ions is reduced.The minim Cu²⁺ ions doping does not almost change the binding energy of Fe₂p_1/2 in LiFePO_4.According to the experiment results,we conclude that most of the Cu²⁺ ions substitute the Fe²⁺ ions in LiFePO₄ when a …

In Situ Measurement Of Chloride Concentration And Ph Distribution In The Crevice During The Crevice Corrosion Of Copper Electronic Board, Min Zhang, Xiang-Dong Zhuo, Chang-Jian Lin

Journal of Electrochemistry

Although the crevice corrosion of metals had been extensively studied in the past years,it remained lack of direct experimental information of the micro chemical environments and electrochemical conditions inside the corroding crevice.The distribution of chloride concentration and local pH in the occluded area are the most crucial factors in development of crevice corrosion.The array probes in one dimension of Ag/AgCl and IrO₂ array were developed in this work to in situ follow the distribution of chloride concentration and local pH in the occluded area during the crevice corrosion propagation.Based on a designed simulated crevice corrosion system in 0.5mol/L NaCl …

A Study On Supercapacitor Based On Aligned Carbon Nanotubes, Xiao-Yan Ye, Yan-Zhi Wang, Hai-Yan Song, Zhuo Sun, Pin-Gang He, Yu-Zhi Fang

Journal of Electrochemistry

Large scale vertically aligned carbon nanotubes(ACNTs) with uniform length and diameter were prepared by the pyrolysis of iron(Ⅱ) phthalocyanine at low pressure.The ACNTs were activated by electrolyte-activation,acid-activation or electrochemical activation.The performance of the capacitor based on activated ACNTs was characterized by cyclic voltammograms which was of rectangular shape,impedence spectroscopy in which the phase is above 80° and the result specific capacitance was 16～32 F/g,which suggest that the ACNTs are the promising material for the supercapacitor.

Preparation And Electrochemical Performance Of Ordered Mesoporous Titanium Phosphate As Cathode Material For Li-Ion Battery, Qiong Wang, Attia Adel, Zhi-Cong Shi, Yong Yang

Journal of Electrochemistry

Ordered porous titanium phosphate materials were prepared by using the surfactant template combined with the sol-gel method. The samples were characterized by small angle X-ray diffraction(SA-XRD) method, N₂ adsorption/desorption techniques,high resolution transmission electron microscopy(HRTEM) and element analysis. It is found that the calcination temperature is a big influence on the porous structure, and electrochemical performance of the titanium phosphate materials, and the mesoporous titanium phosphate showed good performance in the electrochemical test, the first discharge capacity is 94 mAh/g at the current density of 150 mA/g. On the other hand, the no porous material with a low capacity of …

Synthesis Of Adipic Acid From Cyclohexanol By Electrochemical Oxidation Using Cr2O72-/Cr3+ As Indirect Oxidant, Zhen-Hai Liang, Yu-Qing Cui, Hong-Yan Sun

Journal of Electrochemistry

Adipic acid was synthesized by electro-oxidation of cyclohexanol taking Cr₂O₇^2-/Cr³⁺ as indirect oxidant.The best technological conditions were optimized by orthogonal experiment.The optimum condition are as follows: the temperature is 35 ℃,ratio of crude material is n(cyclohexanol)∶n(Cr₂O₇^2-)=0.4∶1 and concentration of H₂SO₄ is 4 mol·L^-1.Under these conditions,the yield of adipic acid can reach 70.29%.Moreover,The effects of concentration of Ag₂SO₄,(NH₄)₂SO₄,H₂SO₄and current density on the formation of Cr₂O₇^2-were also …

Mechanism Of The Cathode Reduction Of Ti(Ⅳ) In Molten Na3Alf6-Alf3, Hai-Bin Sun, Xiu-Rong Zuo, Zhi-Guo Zhong, Xue-Hui Hu

Journal of Electrochemistry

The mechanism of TiO₂ electrode process has been investigated by cyclic voltammetry and chronopotentiometry on the tungsten filament in molten Na₃AlF₆-AlF₃ salts at 990 ℃.The experimental results showed that electrochemical reduction of Ti(Ⅳ) precede were two steps,firstly Ti(Ⅳ) was reduced to Ti(Ⅱ),then Ti(Ⅱ) was reduced to Ti,namely: Ti(Ⅳ)→Ti(Ⅱ)→Ti.

Interfacial Electrochemical Behavior Of Fibrinogen On Pt Electrode, Song-Mei Chen, Jian-Zhang Zhou, Zhong-Hua Lin, Dong-Mei Zeng, Nan Huang, Guo-Jiang Wan

Journal of Electrochemistry

The interfacial electrochemical behaviors of fibrinogen on Pt electrode in phosphate buffered solution(PBS) was investigated by using cyclic voltammetry and electrochemical in-situ FTIR spectroscopy.The cyclic voltammetry results demonstrated that the fibrinogen adsorb on Pt electrode and impede the interfacial charge transfer of hydrogen ion reaction process as well as of oxygen reduction process,which is increased with higher scan rate.The cyclic voltammetry spectra of platinum absorbed with fibrinogen in K₃[Fe(CN)₆] and K₄[Fe(CN)₆]·3H₂O solutions shows that the fibrinogen can partly decrease the oxidation and reduction current peaks.There is no specific anodic and …

Effects Of Oxidation Methods On The Stability Of Coooh Conductive Network In Foam Nickel Electrodes, Xiao-Feng Li, Yan-Wei Wei, Hui-Chao Dong

Journal of Electrochemistry

Two kinds of the cobalt oxyhydroxide conductive networks in foam nickel electrodes were prepared by different methods i.e.the electrochemical-oxidation(EO) and chemical-oxidation(CO) and which redox behaviors were studied by using cyclic voltammetry and X-ray diffraction measurements.The results show that the CoOOH(CO) has better redox reversibility than CoOOH(EO) and the structure of the former can be kept when nickel electrodes are subjected to a negative potential.Thus,98.7% capacity retention is demonstrated on nickel/metal-hydride batteries with CoOOH(CO) conductive network after being imposed over-discharge state storage;on the contrary,only 83.3% capacity retention is found on the batteries with CoOOH(EO) conductive network.

The Influence Of The Sputtering Power On The Structural And Electrochemical Properties Of Tin Oxide Films, Min-Zhen Cai, Jie Song, Ming-Sen Zheng, Qi-Hui Wu, Sun-Tao Wu, Quan-Feng Dong

Journal of Electrochemistry

Tin oxide films were deposited on silicon substrates at room temperature using the radio frequency(RF) magnetron sputtering with different sputtering power.The influence of sputtering power upon the crystal structure,surface morphology and electrochemical properties of tin oxide films were then investigated.The XRD and SEM results illustrate that the phase of tin oxide thin films changed from amorphous to crystalline and the grain size augments with the increase of the sputtering power.The constant current charge and discharge cycle tests imply that the initial irreversible capacity loss of Li/tin oxide batteries increase and which capacity decrease as the sputtering power increases.The sputtering power …

Effect Of Au At Different States On Electrocatalytic Performance Of Pd Catalyst For Oxidation Of Formic Acid, Xin Wang, Ya-Wen Tang, Tian-Hong Lu

Journal of Electrochemistry

Using liquid-reduction or complex-redution method,four catalysts,i.e,the Au/C,Pd/C,Pd-Au/C-T and Pd-Au/C-H were preparated and which electroanalytic activities and stabilities for the oxidation of formic acid were compares.It was found that the Au/C catalyst has no electrocatalytic activity,and the Pd/C catalyst possesses the good electrocatalytic performance for the oxidation of formic acid.The addition of Au into the Pd/C catalyst can increase the electrocatalytic activity and stability.Especially,the electrocatalytic activity and stability of the Pd-Au/C-T catalyst with the alloy of Pd and Au are better than that of the of the Pd-Au/C-H catalyst,in which,Pd and Au do not form the alloy.The investigation of its reason …

Molten Salt Treatment Of Mno2 And Investigation On Supercapacitor Properties, Ye Chen, Zun-Bo Zhang, Wei Zhang, Liang Liu, Zhi-Min Liu

Journal of Electrochemistry

The MnO₂ prepared by solid phase method is treated by KCl-NaCl-LiCl molten salt system.The XRD patterns indicated that the crystal structures of MnO₂ sample have had the α-MnO₂ and γ-MnO₂ phase,the crystallinity of sample is increased after treated by molten salt.The electrochemical properties were tested by cyclic voltammetry,constant current charge/discharge and AC impedance.The result shows that the supercapacitor performance of the treated material has improved.The specific discharge capacitance of the treated sample are 129.07 F·g^-1,increased by 27.88% compared to 100.94 F·g^-1 of untreated sample.Long cycle life and high coulombic efficiency were also demonstrated …

Synthesis Of 2,2′-Dichlorohydrazobenzene Using An Ion Exchange Membrane, Chao Zhang, Pei-Jin Li

Journal of Electrochemistry

Using an ion exchange membrane as a separator,the 2,2′-Dichlorohydrazobenzene is synthesized by the electrolytic reduction of o-chloronetrobenzene.The effects of electrode activation condition,current density,electrolyte temperature on electrolytic reduction are discussed.It was found that the optimum reaction temperature is 80 ℃.When the electrolyte concentration was 30% NaOH at the anode and 10% NaOH at the cathode,current density is 4.2A/dm²,the current efficiency reached 73% and yield is 83%.

Potentiometric Response Of Glucose On Mno2-GoX Carbon Paste Electrode, Cai-Juan Wang, Xiao-Ya Hu

Journal of Electrochemistry

A novel carbon paste electrode(CPE) modified with MnO₂ and glucose oxidase(GO_x), is reported. Different factors, such as the effect of supporting electrolyte, pH of solutions,various paste glues, the amount of MnO₂ and temperature, which may influence the determination of H₂O₂ and glucose were tested to optimize. Based on above, potentiometric determination of glucose was achieved in neutral solution and at 35 ℃, the electrode gave a response of 36.12～34.62 mV/pG lucose between 2.0×10^-5 mol·L-1 and 5.2×10^-3 mol·L^-1 with a detection limit of 3.3×10^-6 mol·L^-1. Moreover, this kind …

Square Wave Stripping Voltammetric Behaviors Of Rutin On Glassy Carbon Electrode And Its Application, Jun Hua, Xiao-Ying He, Fang Liao, Qing-Tao Zhu

Journal of Electrochemistry

The electrochemical behaviors of rutin(Rt) at glassy carbon electrode were studied by square wave stripping voltammeter in the presence of 0.1mol·L^-1HAc-NaAc buffer solution(pH=3.0).The sensitive oxidation peak of rutin was observed and which potential peak is 0.46V(vs.SCE).The experimental parameters,such as pH value,deposition potential and deposition time were investigated and selected.The peak currents were proportional to the concentration of rutin in range of 5.0×10^-8 mol·L^-1~1.0×10^-6mol·L^-1,and the linear regression coefficient equaled 0.99799,the detection limit was 1.1×10-8 mol·L^-1.This method was applied to the determination of rutin content in tablet with satisfactory results.

Corrosion Electrochemical Behavior Of Az31 And Az61 Magnesium Alloys In Simulated Sea Water, Ling-Jie Li, Sheng-Hai Yu, Jing-Lei Lei, Chuan-Pu Liu, Sheng-Tao Zhang, Fu-Sheng Pan

Journal of Electrochemistry

Tafel polarization curves and electrochemical impedance spectroscopy(EIS) techniques were employed to investigate the corrosion electrochemical behavior of AZ31 and AZ61 magnesium alloys.Scanning electron microscopy(SEM) was used to observe the alloy microstructure and corrosion morphology.The variation of the bulk corrosive medium pH with immersion time was recorded during the exposure of the alloys to simulated sea water.Results show that AZ61 magnesium alloy exhibits much better anti-corrosion ability than AZ31 magnesium alloy.The different corrosion behavior between the two magnesium alloys is correlated with their different content of Al alloying element.The higher content of Al in AZ61 alloy leads to the homogenerous microstructure …

The Determination Of Vitamin C By Bromophenol Blue Modified Glassy Carbon Electrode, Shu-Lin Zhang, Min-Jiao Li, Yi Luo, Xiao-Bo Wang

Journal of Electrochemistry

The content of ascorbic acid of(vitamin C) was analyzed by using fast cyclic voltamment with bromophenol blue(BPB) modififed GC-electrode,and which experimental conditions were optimiged.The results showed that the BPB modified GC-electrode had the good stability and anti-jamming faculty for analysing the content of ascorbic acid.A linear relationship between the peak current and concentration of vitamin C in the range of 0.0050~0.1500 g·L^-1 was obtained,which related coefficient and the detection limit are-0.9991 and 0.0010 g·L^-1,respeclively.The method has satisfactory results.

Modeling The Physical Properties Of A Homologous Series On The Melting Temperatures And Densities Of N-Alkanes And Their Simple Alkyl-Derivatives, Antun Rubčić, Jasna Rubčić, James Chickos

Chemistry & Biochemistry Faculty Works

No abstract provided.

Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The physical properties of polymers at interfaces can be quite different from those in bulk due to the interaction between the absorbed polymer and the surface. This phenomenon can be probed through the dynamic behavior of the polymer chains at the interface which can be experimentally probed by techniques such as nuclear magnetic resonance spectroscopy (NMR),1 viscoelasticity, and calorimetry. At the polymer-air interface, polymer chains have more flexibility than those at the polymer-substrate interface. On the other hand, at the silica-polymer interface, where chains are more restricted on the surface, a higher glass transition temperature (Tg) results as compared with …

Dynamics Of Adsorbed Pma-D₃ - Effect Of Substrate, Frank D. Blum, Burak Metin, Macduff O. Okuom

Chemistry Faculty Research & Creative Works

In the last few years, our group has focused much of our attention on studying the dynamics of polymers adsorbed at interfaces. Much of our work, to date has been on labeled poly(vinyl acetate)-d3 (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3)2 on silica. We have been able to probe the effects of adsorbed amount,3 molecular mass,4,5 and the effect of overlayer.6 These studies have provided a view of the adsorbed polymer consistent with a motional gradient in the layer with the more mobile segments being those at the air-polymer interface and the less-mobile segments at the substratepolymer interface. However, we have not …

Glass Transition Behavior Of Poly(Methyl Acrylate) End-Grafted By Atrp To Amorphous Silica, Manikantan B. Nair, Frank D. Blum

Chemistry Faculty Research & Creative Works

Ultra-thin polymer films attached to solid substrates (supported films) have attracted significant interest in recent years. Supported films are used in the design of advanced materials like photoresists, lubricants and other electronic devices. Glass transition temperatures (Tgs) of supported polymer films have also been of significant interest. The Tg has been shown to depend on the thickness of the polymer film on the surface and the inherent nature of the surface. The effect of end-grafting of a polymer chain to a surface, on the Tg of the polymer has been studied previously.1 Reports on the study of glass transition behaviors …

Dynamics Of Pipa-D₇ On Silica Surface, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

Molecular motion of polymer chains is an important determinant in understanding the physical properties of polymeric materials. Glass transition temperature (Tg) is a physical property of polymers, which is of primary interest. The study of the dynamics of polymer segments assists in understanding the dependence of Tg on polymer structure.1 For decades, studies have addressed the molecular motion in various polymers. Some of them have probed the dynamics of polymer backbones.2,3 the properties of a polymer at an interface may change because of the type of polymer, the substrate, or other variables. The side chain of a polymer can also …

Activation Energy Of Surface Diffusion And Terrace Width Dynamics During The Growth Of In (4×3) On Si (100) - (2×1) By Femtosecond Pulsed Laser Deposition, M. A. Hafez, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The nucleation and growth of indium on a vicinal Si (100) - (2×1) surface at high temperature by femtosecond pulsed laser deposition was investigated by in situ reflection high energy electron diffraction (RHEED). RHEED intensity relaxation was observed for the first ∼2 ML during the growth of In (4×3) by step flow. From the temperature dependence of the rate of relaxation, an activation energy of 1.4±0.2 eV of surface diffusion was determined. The results indicate that indium small clusters diffused to terrace step edges with a diffusion frequency constant of (1.0±0.1) × 10¹¹ s^-1. The RHEED specular …

A Study Of The Interaction Of Thioindigo Dye, With Several Inorganic Host Materials, Alejandra Ramirez

Open Access Theses & Dissertations

Maya Blue has been the focus of numerous studies and is believed to be a mixture of palygorskite clay and indigo dye.^1,2 Several derivatives of this pigment have been developed with intriguing properties. For instance, the dye thioindigo reacts with the palygorskite clay to exhibit a broad range of colors from red to blue under UV-Vis excitation. Based on FT-Raman and computer simulation, previous work performed in our group could relate indigo and thioindigo interaction to the aluminum sites in the framework. super>3,4

The work performed with other inorganic host materials such as, layer structures and zeolites have …

Oligo(Vinylidene Fluoride) Langmuir-Blodgett Films Studied By Spectroscopic, Rafal Korlacki, J. Travis Johnston, Jihee Kim, Stephen Ducharme, Daniel W. Thompson, Vladimir M. Fridkin, Zhongxin Ge, James M. Takacs

Stephen Ducharme Publications

Thin films of amphiphilic vinylidene fluoride oligomers prepared by Langmuir–Blodgett deposition on silicone substrates were investigated by comparing experimental and theoretical mid-infrared (IR) spectra. The experimental spectra were obtained using infrared spectroscopic ellipsometry. Theoretical spectra were calculated using density functional theory. Excellent correspondence of major IR bands in both data sets shows that the molecular backbone is oriented with the long axis normal to the substrate plane. This is in contrast to poly vinylidene fluoride[1] LB films, in which the polymer chains are parallel to the substrate.

Interaction Between Metal Fission Products And Triso Coating Materials, Clemens Heske

Fuels Campaign (TRP)

This project focuses on the chemical bonding and interface formation of metal fission products with the coating materials used in tri-isotropic (TRISO) fuel particles for gas-cooled reactors. By combining surface- and bulk-sensitive spectroscopic and microscopic methods, intermediate chemical phases at the interface, intermixing/diffusion behavior, and the electronic interface structure for different coating materials and metals are examined.

In detail, the project studies the interface formation of Pd, Cs, and Ag with SiC and pyrolytic carbon. Using SiC single crystals and highly-ordered pyrolytic carbon (HOPG) as substrates, interfaces are prepared under controlled conditions in an ultra-high vacuum environment and are studied …