Physical Chemistry Commons^™

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 …

Adsorption Of Polyaspartic Acid From Sulphur Acid Solution On Carbon Steel And Its Corrosion Inhibition, Rong-Jing Cui, Ning Gu, Chun-Mei Li

Journal of Electrochemistry

The role of Polyaspartic acid in the corrosion inhibition of 45# carbon steel in sulphuric acid solution has been investigated by polarization curve andelectrochemical impedance spectroscopy (EIS). The influences of the concentration and the temperature of PASP on the corrosion inhibition efficiency were determined. The results indicated that the PASP as the corrosion inhibitor mainly inhibitated the anode; within the experiment temperature, the inhibitor efficiency decreased with the raising of the temperature and PASP had a good inhibiting performance at 10℃, the corrosion inhibition efficiency of PASP for carbon steel increased with the increase of the concentration of PASP when …

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 …

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 …

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 …

Surface And Sructure Investigations Of Membrane Electrode Assembly In Dmfc Lifetime Testing, Xuan Cheng, Cheng Peng, Meng-Di You, Jing Liu, Ying Zhang

Journal of Electrochemistry

The lifetime and performance of a direct methanol fuel cell (DMFC) were investigatedto understand the correlation between thestructure of catalysts/membrane and cell performanceversus time. The cell polarization and performance curves were obtained during the DMFC operation with the time. The catalysts and Nafion membrane of the membrane electrode assembly (MEA) from the lifetime test were comprehensively examined by XRD, HRTEM, FTIR and Raman spectroscope techniques. The results revealed that there was significant performance degradation during the first 200 hours operation; while the degradation was slowing down between 200 and 704 hours operation. The degradation became worse after 1002 h operation. …

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 …

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 …

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.

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.

Nafion Emulsion Method For Fuel Cell Membrane-Electrode-Assembly Preparation, Chao-Yang Xia, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

A Nafion emulsion method for fuel cell membrane-electrode-assembly (MEA) preparation was reported for the first time in this paper. 5 %(by mass) Nafion alcohol solution and non-polar solvent (e.g., cyclohexane) were ultrasonicallymixed to produce Nafion emulsion. The catalyst ink prepared using the thus-obtained Nafion emulsion can be directly cast onto Nafion membrane to make MEA. This method is simple in operation, and effectively preventsthe Nafion membrane swelling, hence is suitable for large-scale application. The MEA thus-prepared showed comparable catalyst efficiencywith respect to the popular transfer-method, and the preliminary performance in room-temperature H₂/O₂ fuel cell test was satisfying.

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.

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.

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′ …

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 …

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 = …

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.

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 …

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 …

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.

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.