Chemistry Commons^™

Electrochemical Behavior And Determination Of Curcumin, Ping Wu, Wei Chen, Ya-Feng Zhang, Xin-Hua Lin

Journal of Electrochemistry

In 0.1 mol/L phosphate buffer solution (pH 3.0), the voltammetry behaviors of curcumin at a glassy carbon electrode have been studied.One pair of current peaks of the voltammogram may be attributed to a reversible one-electron transfer of curcumin molecules at the glassy carbon electrode.A new method, the differential pulse voltammetry, for curcumin determination is described. The adsorptive potential of curcumin is (+0.8) V(vs. SCE),while its peak potential of curcumin is +0.386V (vs. SCE). The peak current is proportional to the concentration of curcumin over the rage of 1.0×10^-8 mol/L~2.5×10^-7 mol/L. A detection limit of 4.0×10^-9 mol/Lof curcumin …

Research Progresses In A Flow Redox Battery, Quan-Feng Dong, Hua-Min Zhang, Ming-Gang Jin, Ming-Sen Zheng, Ya-Ding Zhan, Shi-Gang Sun, Zu-Geng Lin

Journal of Electrochemistry

As a large scale electrochemical storage device, flow redox battery in which the active materials are flowing electrolytes is different from the common batteries employing solid or gas materials as an electrode. In this paper we introduced flow redox battery in brief, reviewed its development and actual state on (study). The main problem existed in the new device was discussed when viewed with its future developments.

The Growth Of Aluminide-Layer During The Hot-Dipping Al-(Si) Coating Onto 430 Stainless Steels, Peng-Chicao Chen, Chaur-Jeng Wang, Yu-Chang Lin, Hsuan Ching

Journal of Electrochemistry

The 430 stainless steels have been hot dipped in the molten Al-6.5%Si melts from 680 to 800℃, respectively. The effects of the hot dipping temperature and time on the thickness of the internal alloy layer have been investigated. The activation energy of the growth kinetic of aluminized layer was also calculated. The results showed that the thickness of aluminized layer increased with increasing dipping time and temperature. Besides, the growth kinetic of aluminized layer obeys parabolic rate law. The FeAl₃ and Fe₂Al₅ were formed by the inward diffusion, and the interface of intermetallic layer will be …

The Application Of Astm C1202-93 On Evaluating The Performance Of Anti-Corrosion Of Concrete, Yuan-Chen Yuan, Tsung-Yueh Tu, Chao-Lung Hwang

Journal of Electrochemistry

The test of chloride ion penetration based on the standards of ASTM C1202-93 is applied to evaluate the anti-corrosion performance of concrete in this research. Concrete specimens were produced according to ACI 318-89 mixture proportioning design and the Desenfied Mixture Design Algorithm (DMDA) and were measured the 6-hour coulombs at the age of 91 days. Results show that w/b is not the factor influencing chloride penetration of ACI concrete, as the ion penetration of ACI specimens is all higher than 2 000 Coulombs and can even be poorer than 10 000 Coulombs. With a proper amount of pozzolanic material, the …

Effect Of Sintering Temperatures On Synthesis Of Mgco0.4Mn1.6O4 Positive Materials In Magnesium Ion Battery, Xiu-Ling Gao, Li-Fang Jiao, Hua-Tang Yuan, Jian-Sheng Cao, Ming Zhao, Hai-Xia Li, Yong-Mei Wang

Journal of Electrochemistry

The cathode material MgCo_0.4Mn_1.6O₄ for magnesium ion battery was synthesized by sol-gel method. The TG-DTA and XRD analyses showed that the prepared samples has simple spinel structure. Effect of annealing temperature on electrochemical properties was researched. The result shows that the sample sintered at 700℃ has the best electrochemical properties.

The Research Of Nano-Sized Nio Anode Materials For Lithium Ion Batteries, Jun-Mei Yan, Jing Zhang, Yong Yang

Journal of Electrochemistry

The nano-sized NiO materials were synthesized by solid phase method and sol-gel method. The synthesis conditions were optimized by DSC and TG techniques. The sol-gel method was optimized by changing the solvent and regulating the solution's pH for preparing NiO material. The structure and morphology of the materials were also characterized by means of XRD and TEM techniques, and the electrochemical performances of the materials were studied by the galvanostatically charge and discharge experiments.

Electrochemical Remedy And Analysis For The Environment Based On The New Polymer-Dna Composite Material., Noor Feuza Hussain

Electronic Theses and Dissertations

In this work a new material, the conducting polymer-DNA composite, has been reported for the first time due to its promise in micro extraction, transfer, and release of cations under controlled potential conditions by using electrochemically assisted solid phase micro extraction (SPME). The Polypyrrole/DNA composite can be formed easily by oxidation of pyrrole monomers in the presence of chromosomal DNA by electropolymerization. Environmental significant pollutants such as Cd, Pb, Hg, Co, Zn, Cu, and Bi metal ions can be extracted from the aqueous solution and are able to be transferred to another medium defined as the release solution where the …

Electrochemical Stability Of Pva Alkaline Gel Polymer Electrolyte Membranes, Jun-Hong Wang, Jian-Min Liu, Hua-Bin Yang, Zuo-Xiang Zhou

Journal of Electrochemistry

Polyvinyl alcohol (PVA) alkaline polymer gel electrolyte (GPE) membranes were successfully prepared by a solution-casting technique and their electrochemical stabilities were investigated. The electrochemical impedance spectrum (EIS) results showed that the ionic conductivity of the PVA alkaline GPE membranes first increased with the increase of KOH content, then decreased with the further increase of KOH. When the weight percentage of the KOH in the PVA alkaline GPE membrane approached to 42%, it exhibitedthe highest ionic conductivity of 2.01×10^-3 S/cm at room temperature (R.T.). The X-ray diffraction (XRD) results revealed that with the increase of KOH the crystalline of the …

A Preliminary Study Of Electrocrystallization Of Bismuth On Glassy Carbon, Min-Li Yang, Zhan-Jun Zhang

Journal of Electrochemistry

The electrocrystallization of bismuth on glassy carbon electrodes (GCEs) from nitrate solutions was studied by cyclic voltammetry and chronoamperometry. Cyclic voltammograms exhibit a crossover between the cathodic and anodic branches, characteristic of the formation of bismuth nuclei on GCEs, and show that the bismuth electrocrystallization on GCEs is a diffusion-controlled reaction. The current transients were analyzed with the Scharifker and the Heerman equations. With the increaseof Bi³⁺ concentration, the non-dimensional plots leaned to the theoretical curve for 3D instantaneous nucleation and growth. The overpotential dependence of nucleation and growth mechanism was also found. With the increase of overpotential, the …

The Synthesis, Characteristics And Performance Of Cnt Composites As Anodic Materials In Litium-Ion Battery, Quan-Feng Dong, Ming-Sen Zheng, Zhen-Cai Huang, Ming-Gang Jin, Ya-Ding Zhan, Zu-Geng Lin

Journal of Electrochemistry

As an anodic material for lithium ion battery the carbon nano-tube (CNT) and some compounds based on tin have ever been investigated intensively. The fruited progress has not been made yet, however. In this paper the composites of CNT and Sn/SnO₂ were synthesized employing two methods and characterized by SEM and XRD. And the electrochemical performance of the composites was investigated.

Preparation And Characterization Of Mcm-41/Pvdf-Hfp Composite Microporous Polymer Electrolytes For Li-Ion Batteries, Zuo-Feng Chen, Yan-Xia Jiang, Quan-Chao Zhuang, Quan-Feng Dong, Shi-Gang Sun

Journal of Electrochemistry

MCM-41/vinylidine fluoride-hexafluropropene copolymer (PVdF-HFP) composite microporous polymer electrolytes were prepared with mixed solvent of N, N-Dimethylformamide (DMF) and acetone. The influence of MCM-41 and nano-SiO₂ on the porous structure of the microporous polymer electrolytes were studied with SEM. The results show that MCM-41 could take the place of the plasticizer in the process of making pores, and bring the preparation of microporous membranes easily. The preliminary electrochemical tests showed that the ion conductivity of composite microporous polymer electrolyte with 10% MCM-41 was about 10^-3 S cm^-1, and the performance of batteries was improved. The mesoporous MCM-41selected …

Potential Fluctuations Of 7075 Aluminum Alloy Under Thin Electrolyte Layers, Su-Jing Chen, Qing-Ming Yuan, Jian-Ping He, Xiao-Lei Liu

Journal of Electrochemistry

Lens tissues adsorbing 3.5% sodium chloride solution were used to simulate thin electrolyte layers. The 7075 aluminum alloy was immersed under the thin electrolyte layers for 0, 4, 6, 8 and 12 h respectively. Then the fluctuations of natural-corrosion potentials of the alloy were monitored. The fluctuations of natural-corrosion potential were observed rather small in the initial corrosion stages after 6h immersion, and the positive peaks of potential appeared. However the amplitudes reached 20mV after 4h and 12h immersion. The RMS of natural-corrosion potentials decreased with corrosion time at first and then increased. It reached a minimum at 4 h. …

Application Of Nickel Foam Electrode For Electroreduction Intermediate Of Purine, Hui-Wen Yang, Xi-En Hu, Xue-Jun Wang

Journal of Electrochemistry

Nickel foam with weight uniformity, good porosity ,pore size and low resistivity as a three-dimensional cathode was used in a filter-press electrochemical reactor. The H₂SO₄ as supporting electrolyte, separator of cation ion exchange membrane, and the lead plate as an anode were used. The cyclic system consisted of electroreduction reactor, pump, store tank and ampere meter. NAU was electroreduced in the cathode chamber of the reactor. Purine intermediate was synthesized with DAU, and the results were compared with those of iron powder reduction process. A peak current in the electroreduction process was detected. The current density of …

Investigation On Ru-Ti-Ir-Sn Oxide Anode Coatings For Electrolyzing Seawater, Ke Wang, Yan Han, Lei-Yuan Wang, Xiao-Ling Zhang, Yu-Pu Sun

Journal of Electrochemistry

The anode coatings of Ru-Ti-Ir-Sn oxide with various compositions were prepared by thermal decomposition. The physical and electrochemical properties of the coatings were characterized by scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), accelerated life, current efficiency, anti-Mn²⁺ contamination, polarization curveandcyclic voltammetry tests. The results showed thatthe anode coating with optimized formula possessed excellent overall properties for electrolyzing seawater.

Ni-Mo-P Alloy By Electroless Deposition And Its Properties, Sen-Lin Wang, Xin-Ren Lan, Ting-Ting Huang, Jun-Mo Jin, Ji-Bei Ling, Zhi-Ming Chen

Journal of Electrochemistry

The electroless Ni-Mo-P alloy has been deposited from the alkaline bath containing boric acid as a buffer agent and sodium citrate as a complexing agent. The effect of deposition parameters, such as pH and concentration of (NH₄)₆Mo₇O₂₄·4H₂O on the plating rate, the composition, the structure and the microhardness of the coating was examined. It was found that the presence of molybdenum has an inhibitory effect on the alloys deposition. As a consequence, the percentage of molybdenumin the Ni-Mo-P coatings never reaches high values, which was lower than 20 at%. It …

Structure And Corrosion Electrochemical Properties Of Self-Assembled (3-Mercaptopropyl) Trimethoxysilane Films On Copper Electrode, Ling Huang, Ke-Fa Lin, Fang-Zu Yang, Shu-Kai Xu, Shao-Min Zhou

Journal of Electrochemistry

A self-assembled monolayer of (3-mercaptopropyl) trimethoxysilane(MPTS) was formed on a electrochemical polished copper surface electrode. The corrosion protection abilities of the monolayer were evaluated in 5% NaCl solution using electrochemical linear polarization. The effects of deposition time and silane concentration on corrosion of copper were also discussed. The surface structure of MPTS films was measured by FT-IR and SEM. It was found that the corrosion resistance of copper was reduced markedly owing to the MPTS monolayers formation on copper. The MPTS monolayer retarded the reduction of dissolved oxygen and inhibited the growth of copper oxide in the NaCl solution. FT-IR …

Selective Electroless Copper Plating Micro-Pattern On Ceramics Without Sensitisation And Activation, Zhen-Lin Xu, Qi-Long Guo, Yi-Cheng Shen, Xiong-Chao Zhao, Yan-Ping Hong, Zhi-Jun Gu

Journal of Electrochemistry

The purpose of this article is to provide a new technology of electroless copper plating without palladium activation steps. By combining the technology of laser micro-etching with the new copper-plating bath, copper plating on ceramics was obtained. The experimental results showed that the solution used for copper electroless plating was stable and the copper coating obtained was bright, dense with good electrical conductivity.The line definition was about 40 μm. The electroless Cu films deposited from this system were gentle and required simple operating conditions.

Study On Synthesis Of M-Phenoxy Benzoic Acid By Electrolysis Oxidation Method, Wei Xu, Chong-Tao Zhao

Journal of Electrochemistry

The m-phenoxy benzoic acid was synthesized by oxidation m-phenoxy toluene using Cr(Ⅵ)as oxidation media, which was prepared by electrolysis oxidation of Cr(Ⅲ)in the electrochemical bath using Nafion 417 as a diaphragm, Pb-PbO₂ as an anode and Pb as cathode. The effect factors on the electrochemical oxidation of Cr(Ⅲ)to Cr(Ⅵ)in this electrolysis were studied. Furthermore, the optimal conditions for electronic synthesis of m-phenoxy benzoic acid were also discussed.

Using Electrodeposition To Fabricate Mould For Polymer Microfluidic Chip, Yi Luo, De-Nan Chu, Zhi-Feng Lou, Chong Liu, Li-Ding Wang

Journal of Electrochemistry

Many researches have been focused on polymer microfluidic chip in recent years and the mould plays an important role in its fabrication process. Using electrodepositingmethod to fabricate a metal mould for polymer microfluidic chip has been presented in this paper. An ultra-thick photoresist SU-8 was coated on a pretreated metal plate, after photolithography, nickel was electrodeposited in the patterned SU-8, then was removed the SU-8 to obtain a final metal mould. This methodreduces workload of electrodeposit largely. Applying counter current before deposit, adding additive to solution and vacuum anneal after demould have been used to improve the binding force between …

The Effect Of Oxidant On Structure And Properties Of Pan/Ptfe Conducting Composite Membrane, Chang-Yuan Tao, Jing Chen, Jun Du, Cai-Xin Sun

Journal of Electrochemistry

The PAn/PTFE conducting composite membrane was prepared by means of in-situ permeating chemical polymerization, with (NH₄)₂S₂O₈ and Na₃VO₄ being used as an oxidant respectively. The polymerization-growth behavior of the aniline by using different oxidant was compared. In addition, the oxidant effect on the structure and properties of conducting composite membrane was discussed. The results of SEM micrographs, pore size distribution and electrochemical methods suggested that using either oxidants could also induce the product with small pore size and dense pore structure. Compared with (NH₄)₂S₂O …

Preparation, Characterization And Electrochemical Properties Of Nano Tio2-Cnt-Pt On Ti Substrate Complex Electrode, Dao-Bao Chu, De-Xiang Feng, Jin-Hua Zhang, Xiao-Hua Li

Journal of Electrochemistry

The nanoTiO₂-CNT-Pt on Ti substrate complex electrodes were prepared from precursor of (Ti(OEt)₄) directly hydrolyzed and by cyclic voltammograms electroplating method . The XRD and SEM results showed that the nano TiO₂ (anatase) particle sizes ranged 5~10 nm and the Pt nanoparticle (average size 9nm) dispersed uniformly on nanoTiO₂-CNT film surface. The electrocatalytic activity of Ti/nanoTiO₂-CNT-Pt electrode was investigated by cyclic voltammetry and chronopotentiogram. The results indicated that the Ti/nanoTiO₂-CNT-Pt electrode exhibited very high electrocatalytic activity and stability for the electro-oxidation of methanol at room temperature. When Pt loading …

Initial Process Of Pyrophosphate Copper Electroplating, Shao-Bin Feng, Shi-Bo Shang, Li-Ting Feng

Journal of Electrochemistry

The relationship between the type of on changes of copper electroplating potential time and the adhesion of coating layer was examined by chronopotentiometry. The conception of critical initial current density D_KC was put forward. When the initial working current D_KI was higher than the critical initial current, the iron electrodewas polarized to activation potential of iron surface firstly, then to the activation of the substratesurface, and finally to depositionpotentialof copper ion. The coating deposited on the active surface and had goodadhesion. On the contrary ,when D_KI was lower than D_KC, the coating deposits on the …

Study On The New Type Fe3O4 Composite Anode, Xin-Yong Xiong, Lie-Peng Fan, Mao-Hua Wang, Qi-Long Guo, Yan-Ping Hong, Chang-Hui Huang, Jia-Lin Wu

Journal of Electrochemistry

An ultrafine powder of magnetite has been prepared, and used to prepare the composite anode of Fe₃O₄-Fe by sintering method. The voltage of chlorine evolution, polarization curves, service life and mass loss, and the optimum sintering temperature and the weight ratio of the sintered powder have been investigated. All results showed that the method of preparing the practical Fe₃O₄-Fe composite uniform anode is feasible.

A Comparison On Structural Sensitive Adsorption Of Sb On Au Single Crystalline Electrodes, Jia-Wei Yang, Wang-Huo Shang, Qiong Wu, Bing-Wei Mao

Journal of Electrochemistry

We compare the behaviors of irreversible adsorption of Sb(III) and its reduction, underpotential deposition of Sbon Au(111) and Au(100) as well as mutual interactions of the processes. Based on in-situ scanning tunneling microscopic and cyclic voltammetric results, the substrate structure not only influence anion adsorptionbehavior and thus the Sb adsorption structure, but also the stability of its own structure. On Au(111) surface,the irreversibly adsorbed dense and disordered SbO⁺ film structure remains after reduction of the film; while on Au(100)surface, due to the coadsorption of SO₄^2-, an ordered(2×2)structure is formed after reduction. UPD of Sb on Au(111) …

The Preparation And Performance Of The Aqueous Matrix For Molten Carbonate Fuel Cells, Hua-Xin Lin, Mo-Jie Ceng, Bao-Lian Yi

Journal of Electrochemistry

PVA matrix of MCFC was prepared from the α-LiAlO₂ powder, and polyvinylalcohol(PVA), Compared with the conventional PVB matrix, higher porosity, higher thermal weight loss and smaller maximum pore diameter were achieved for PVA matrix. Single cell was assembled with PVA matrix. At reaction gas pressure of 0.9 MPa, under reaction gas utilization of 20%, at 300 and 428.57 mA·cm^-2, the cell voltage was 0.849 and 0.739 V respectively, and the output power density was 254.7 and 316.7 mW·cm^-2 respectively, which are higher than those of the cell assembled with PVB matrix. During thermal cycles, the cell …

Synthesis Of Novel Alkaline Earth Metal Acetylides, Eva Baker

Renée Crown University Honors Thesis Projects - All

Acetylide complexes of the heavy alkaline-earth metals were first introduced by our group. With our group being interested in how the ligand and donor affect the structural chemistry of the resulting complexes, my project was focused on the detailed analysis of past work and the extension towards new ligand and donor sets. The work required the analysis and development of synthetic procedures towards these highly reactive species.

Past synthetic work in our group had established several synthetic routes towards the target compounds including transamination and toluene elimination. Using toluene elimination, I was able to reproduce the synthesis of M(C≡CSiPh_{3 …}

Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin

Chemistry Faculty Publications

The present report describes the preparation and characterization of several N-2-(trimethylsilyl)ethyl-N-nitrosocarbamates, designed as precursors to thermally unstable secondary N-nitrosocarbamate anions via fluoride-assisted cleavage. X-ray structural studies demonstrate that the core N-nitrosocarbamate moiety has a nearly planar geometry, with an s-E orientation at the N–N bond. DFT calculations (B3LYP/6-31+G(d)) reproduce accurately the structural features of the title compounds and detailed conformational analysis at the same level of theory addresses the long-standing issue of preferred geometries for three classes of related structures: N-nitrosocarbamates, N-nitrosoureas and N-nitrosoamides. Desilylation studies demonstrate that both the …

Fabrication And Studies Of A Novel Ag/Agcl Reference Electrode In High Temperature Molten Chloride Salts, Pei Gao, Xian-Bo Jin, Di-Hua Wang, Xiao-Hong Hu, Zheng Chen

Journal of Electrochemistry

A new method for the easy fabrication of a stable and long life silver/silver chloride reference electrode in molten chloride salts is described in this paper. The method is based on the fact that simply placing the silica glass in molten NaCl or its vapour in the presence of oxygen resulted in satisfactory conductivity for sodium ion and possibly calcium ion in the material.The performance of such made electrode has been investigated in a few typical chloride systems at temperatures ranging from 400 to 900℃. Due to the wholly sealed construction, the reference electrode is stable, temperature-reversible, contamination free to …

Corrosion Behavior Of Mg2-XLaXNi And Mg2-XCeXNi Hydrogen Storage Alloy, Hai-Chang Zhang, Hua-Bin Yang, Jun-Hong Wang, Zuo-Xiang Zhou

Journal of Electrochemistry

The corrosion behavior of Mg-base hydrogen storage alloys has been investigated by potentiodynamic polarization and EIS. The results showed that the corrosion current density (i_corr) and the electrochemical polarized resistance of Mg_2-xCe_xNi alloys decreased with x increase, while i_corr of Mg_2-xLa_xNi alloys increased and the electrochemical polarized resistance of Mg_2-xLa_xNi alloys increased first, then decreased with x increase. SEM results showed that the surface of Mg_1.85Ce_0.15Ni alloy was relatively even while the surface of Mg_2-xLa_xNi alloy had …

Anodic Polarization Behaviors Of Carbon Steel In Bicarbonate Solution, Jing-Mao Zhao, Yu Zuo

Journal of Electrochemistry

The anodic polarization curves of mild steel were measured in sodium bicarbonate solution of various concentrations, and the surface products were analyzed by XPS. Two anodic current peaks and two passive zones are observed in all the curves. When HCO₃^- ions concentration is below 0.1mol/L, the two peaks are so close that the first passive zone is difficult to be observed. When HCO₃^- ions concentration is above 0.1 mol/L, the first peak appears clear, while the second becomes smaller. The XPS results indicate that the out layer of film formed at a higher potential is mainly …