Physical Chemistry Commons^™

A Preliminary Study Of Influence Of The Chain Length Of Alkanethiols On The Electrochemical Behavior Of Redox Self-Assembled Multilayer Thin Films, Yun-Feng Wang, Zhan-Jun Zhang

Journal of Electrochemistry

Alkanethiols and ferrocene derivates were used to construct redox self-assembled double-or triplex-layer thin films, which acted as a model of redox self-assembled multilayer thin films (SAMTFs) to study the in-fluence of alkanethiols chain length on the electrochemical behavior of the SAMTFs. The rate of electron transferreaction decreased exponentially with the distance between the Fc groups and the underlying electrodes. The in-fluence of chain length on the electrochemical behaviors of the SAMTFs was inconsistent under different situa-tions. On the experimental situation of this work, when electroactive groups were closer to the electrodes, SAMTFs by longer chains of alkanethiols displayed stronger electrochemical …

Effects Of Aluminide And Platinum-Aluminide Coatings On The Hot Corrosion Behavior Of Mar-M247 Nickel-Based Superalloy, I.K. Lee, W.T. Tasi, J.T. Lee

Journal of Electrochemistry

This study is to investigate the high temperature hot corrosion behavior of aluminide coating and platinum-aluminide coating on Ni-base superalloy MAR-M247. On the platinum-aluminide, aluminide and the base metal, respectively, by the salt spraying method. The resistances to hot corrosion of platinum-aluminide coating, aluminide coating and the base metal were evaluated by the variations of weight gains. Aluminide and platinum-aluminide coating showed significanty beneficial effect on inhibiting the hot corrosion of MAR-M247. But that of the platinum-aluminide coating was even much better. The aluminide coating surface was composed of β-NiAl, and that of the platinum-aluminide coating was PtAl₂. …

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 …

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.

Cyclic Voltammetry And Surface Enhanced Raman Spectroscopy Of Dissociative Adsorption Of Ethanol On Pt-Ru Electrodes, Bin Zhang, Hai-Hui Zhou, Zu-Biao Wen, Qi-Ling Zhong, Peng Huang, Xiong-Yuan Yang, Bin Ren, Tian

Journal of Electrochemistry

The behaviors of dissociative adsorption of ethanol on roughened platinum-ruthenium electrode with high activity of SERS were studied by using cyclic voltammetry and in-situ surface enhanced Raman spectroscopy, surface enhanced Raman spectra of dissociative adsorption of ethanol on Pt electrode in acid was obtained for the first time. It is shown that the Pt-Ru could lower the over-potential of CO oxidation when compared to Pt electrode. The results show that the ethanol in acid medium can be self-dissociated at Pt-Ru electrode to produce CO, which discourage the further oxidation of ethanol, some information of Pt-C and Pt-C-Pt stretching vibration from …

An Electrochemical Behavior Of Limn2O4 Electrode In Electrolyte Based On Room Temperature Ionic Liquid, Hong-He Zheng, Lei Shi, Shu-Yan Gao, Jian-Ji Wang

Journal of Electrochemistry

The electrochemical behavior of spinel LiMn₂O₄ electrode in ionic liquid electrolyte was investigated by using cyclic voltammetry, galvanostatic charge-discharge and ACimpedance techniques. The results reveal that the spinel LiMn₂O₄ can be effectively cycled in electrolyte based on the ionic liquid with discharge capacity of 108.2mAh/g and Coulombic efficiency of more than 90% in the first cycle at room temperature. Temperature and current density play an important role in the electrode performances. The activation energy for lithium ion transfer through interface between the electrode and the electrolyte was evaluated by AC impedance spectroscopy. The high …

Surface-Enhanced Raman Spectra Of Cytosine Adsorbed On A Roughened Gold Electrode, Yuan-Fei Wu, Jian-Feng Li, De-Yin Wu, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Cytosine adsorbed on a roughened gold electrode has been investigated by using electrochemical cyclic voltammetry and surface-enhanced Raman spectroscopy (SERS). The results indicate that cytosine was adsorbed on the Au electrode in a perpendicular orientation via the N3 position. As the maximum enhancement of ring breathing mode appears at negative potentials compared with other modes, both the electromagnetic enhancement and the charge transfer mechanism were considered to contribute to the SERS intensity. The binding interaction between cytosine and the gold electrode was weakened when the potential was negatively moved. The result also indicates that the SERS technique can be used …

A Conjugate Dissolution/Deposition Behavior In Thin Layer Electrodeposition, Sun Bin, Xian-Wu Zou, Zhun-Zhi Jin

Journal of Electrochemistry

During the electrodeposition of lead, the dendrite deposit segregates from the cathode due to the disturbance of hydrogen gas. The segregated deposit could move toward the anode spontaneously rather than keep stationary. The studies show that this novel phenomenon was caused by the conjugate electrodissolution and electrodeposition reactions taking place at two ends of the isolated segment of the deposit. The mechanism inducing this phenomenon is suggested.

Corrosion Behavior Of Sml, Erw Pipeline Steels Exposed To Seamud, Wei Hua, Xiu-Tong Wang, Rong-Jie Gao, Yan Li

Journal of Electrochemistry

The corrosion behavior of API Spec X60 pipeline steels, including electric resistance welding(ERW) and Seamless (SML) types, in sea mud gathered fromYangtse River estuaryof the East China Sea was investigatedthrough linear polarization resistance, potentio-dynamic polarizationand electrochemical impedance measurements. The result indicate the improved corrosion resistance of SML in sea mud. The oxygen diffusion in the cathode zone determines the corrosion behavior of pipeline steel in sea mud.

Investigation, On The Accelerated Dissolution Of Metal Induced By Afm Tip Scratching And Suppressed By Inhibitors, Jun-E Qu, Xing-Peng Guo

Journal of Electrochemistry

The accelerated dissolution behavior of Cu-Ni alloy induced by AFM tip scratching and the inhibition effect of corrosion inhibitors were investigated. The results showedthat, with a tip loading of 750nN, continuous scan for 30 min in a contact mode on 4×4 μm² of copper-nickel alloy in 1.5mol/L NaCl and 0.01mol/L HCl could enhance the dissolution of the sample and produced pits on the scratched area. Adding inorganic inhibitors, sodium chromateand organic inhibitor dodecylamine, to the solution suppressed the dissolution of copper-nickel alloyinduced by tip scratching, respectively, by improving the surface passivationperformance of metal surface and forming adsorption films on …

Study On The Adsortion Property Of Mdopd On Q235 Steel, Jin-Ying Huang, Jia-Shen Zheng

Journal of Electrochemistry

The weight loss measurement, potentiodynamic polarisation curves, Electrochemical Impedance Spectroscopy and Atomic Force Microscopy were used to evaluate the corrosion inhibition performance of MDOPD in simulated oilfield water. At the same time, the adsorption mechanism of MDOPD on Q235 steels was suggested. The experimental results show the effective corrosion inhibition in the simulated oilfield water. The MDOPD possessesseveral nitrogen atoms as adsorption centres, which has higher active energy at metal surface and has more effective protection function.

Electrocatalytic Oxidation And Degration Of Active Red X-3b By Nanotubes Catalytic Electrodes, Yi Wen, Jian-Hui Fang, Wei-Min Cao, Li-Yi Shi

Journal of Electrochemistry

The catalytic splitting decomposition of carbon nanotubes isprocessed by dispersing with dilute nitric acid and thermal oxidation. Then well-proportionedphenolic resin is mixed in the carbon nanotubes. Then, the carbon nanotubesare made into electrodes by hot-press molding after the process of milling with high speed. The surface of the carbon nanotubes electrodes is analyzed by SEM. Active red X-3B simulated waster water is disposed by carbon nanotubes catalyticelectrode (anode) and stainless steel(cathode). The influencing factors of degradation by current density, concentrationof electrolyte, systemtemperature and pH are investigated. The experimental results indicated that acidiccondition is propitious tothe degradationreaction of organicdyestuff and wastewater …

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.

Electrochemical Reduction Characteristics Of Nitrobenzene At The Copper Electrode, Jin-Hong Fan, Wen-Ying Xu, Ting-Yao Gao

Journal of Electrochemistry

The electrochemical reduction characteristics and transition steps of nitrobenzene aqueous solution at the copper electrode, as well as its reduction mechanism were extensively investigatedby using the techniques such as cyclic voltammetry (CV) and linear scan voltammetry (LSV). The results showed that the reduction peaks of nitrobenzene at the copper electrode were located at 0.58 V and 1.32 V or so (vs. SCE), both acidity and alkalinesolutionsfavoredthe reduction of nitrobenzene. The adsorption of compounds followed by the reduction process, which is controlled by the mass transfer step at higher nitrobenzene concentration. In addition, the higher anaerobic degree led to faster reduction …

5th Asian Conference On Electrochemistry, Acec2005 Held In Shanghai, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

(2+1) Resonance Enhanced Ionization Spectroscopy Of A State Selected Beam Of Oh Radicals, Margaret E. Greenslade, Marsha I. Lester, Dragana C. Radenovic, Andre J.A. Van Roij, David H. Parker

Chemistry

A state-selected beam of hydroxyl radicals is generated using a pulsed discharge source and hexapole field. The OH radicals are characterized by resonance-enhanced multiphoton ionization (REMPI) spectroscopy via the nested D  and 3  Rydberg states. Simplified spectra are observed from the selected ∣M_J∣ = 3/2 component of the upper Λ-doublet level of the lowest rotational state (J = 3/2) in ground (v″ = 0) and excited(v″ = 1–3) vibrational levels of the OH X  state. Two-photon transitions are observed to the D (v′ = 0–3) and 3 (v′ …

Fluorescence-Dip Infrared Spectroscopy And Predissociation Dynamics Of Oh A (V=4) Radicals, Erika L. Derro, Ilana B. Pollack, Logan P. Dempsey, Margaret E. Greenslade, Yuxiu Lei, Dragana C. Radenovic, Marsha I. Lester

Chemistry

Fluorescence-dip infrared spectroscopy, an UV-IR double-resonance technique, is employed to characterize the line positions, linewidths, and corresponding lifetimes of highly predissociative rovibrational levels of the excited A  electronic state of the OH radical. Various lines of the 4←2 overtone transition in the excited A  state are observed, from which the rotational, centrifugal distortion, and spin-rotation constants for the A  (v = 4) state are determined, along with the vibrational frequency for the overtone transition. Homogeneous linewidths of 0.23–0.31 cm⁻¹ full width at half maximum are extracted from the line profiles, demonstrating that the N = …

The Electrochemical Separation Of Curium And Americium: Quaterly Report April - June, 2005, David W. Hatchett, Kenneth Czerwinski

Separations Campaign (TRP)

This research report outlines the current status and progress associated with the electrochemical separation of Curium and Americium.

Results

• We have completed the electrochemical investigation in of the Ce³⁺/Ce⁴⁺ redox couple and have determined the optimum experimental conditions.

• Computer modeling of the cerium using the JChess speciation-modeling program has been completed for the Ce redox couple. Traditional complexing ligands such as EDTA, oxalate, NTA, phosphate, acetate, and sulfate have been purchased and will be used to initiate the complexation and electrochemical characterization.

• Electrochemical investigations have continued on the Eu²⁺/Eu³⁺ redox …

Innovation In Molten Salt Electrochemistry, Di-Hua Wang, Zheng Chen

Journal of Electrochemistry

Recent research development in molten salt electrochemistry at the Electrochemical Research Centre of Wuhan University is briefly reviewed. Attention is first paid on the preparation of silicon and its binary alloys, as well as oxide based functional materials. In addition, the quartz sealed Ag/AgCl reference electrodes suitable for high temperature molten salts are described. Focus is also given to two types of metal based cavity electrodes that are capable of loading micrograms of oxide powders and hence allow fast and reproducible measurements for the electrochemical behaviour of the powders in molten salts. The article finishes by highlighting the concept of …

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 …

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 …

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 …

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 …

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) …

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.

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 …

Oscillographic Determination Of Ethamsylate, Hong-Gang Ni, Hong-Fang Zhang, Jian-Bin Zheng

Journal of Electrochemistry

In 0.2 mol L^-1 NaOH solution, ethamsylate can yield a sensitive incision on cathodic branch of dE/dt-E osillogram at 0.3V (vs. SCE). Based on the oscillographic characteristic, a second order differential simple oscillographic voltammetry for determination of ethamsylate in tablet and injection is presented in this paper. The peak height on second order differential simple oscillographic voltammogram is linearly proportional to concentration of the ethamsylate in the range of 1.5×10^-5～3.4×10^-4 mol·L^-1 with a 0.9921 correlation coefficient and a detection limit of 6.0×10^-6 mol·L^-1 for ethamsylate. The relative standard deviation is 2.1% for the …

Fabrication Of Nano Capacitor And Its Electrical Properties, Ling Liu, Qin Zhou, Neng-Qin Jia, Zhi-Yu Jiang

Journal of Electrochemistry

A step-by-step assembling method was developed for preparing nano capacitors using anodic aluminum oxide (AAO) membrane as templates. The nano capacitor consisted of three parts: electrochemically polymerized PPy electrode/ el ectrochemically precipitated porous TiO₂ separator/chemically polymerized PPy electrode, and demonstrated the charge/discharge behavior as a typical electrochemical supercapacitor with good cyclic ability.