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Full-Text Articles in Physical Chemistry

The Roles Of The Width Of Gas/Liquid/Solid Three-Phase Boundary Zone Of Dispersion Water Films In Atmospheric Corrosion Of Metals, Wang Jia, Jing Jiang Nov 2010

The Roles Of The Width Of Gas/Liquid/Solid Three-Phase Boundary Zone Of Dispersion Water Films In Atmospheric Corrosion Of Metals, Wang Jia, Jing Jiang

Journal of Electrochemistry

The roles of TPB(Three-Phase Boundary) width in the corrosion processes of metals under dispersed water films were investigated by electrochemical techniques combined with contact angle measurement.It is found that both cathodic limiting current density and corrosion current density linearly increases with increasing the TPB width,confirming the important role of TPB width in gas/liquid/solid multiphase corrosion systems.Based on above results,the effect of water film thickness on atmospheric corrosion rate was quantitatively evaluated by the TPB width.


Research On Nafion/Sio_2 Composite Membrane In All Vanadium Redox Flow Battery, Dong-Dong Liu, Mao-Cai Lin, Tao Guan, Qing-Chun Yu Nov 2010

Research On Nafion/Sio_2 Composite Membrane In All Vanadium Redox Flow Battery, Dong-Dong Liu, Mao-Cai Lin, Tao Guan, Qing-Chun Yu

Journal of Electrochemistry

The Nafion117/SiO2 composite membrane was prepared by sol-gel method.The results showed that,during composite membrane preparation process,the ratio of MeOH and TEOS did not affect the penetration rate of VO2+ basically,however,the lowest permeability of 427×10-9cm2/s in the membrane was achieved while hydrolysis time was 10 min and natural drying for 24 h after hydrolysis,which reduced by 52 times than that in Nafion117 membrane.The SEM tests proved that SiO2 grains grew bigger in the composite membrane during the natural drying,and most of the holes in Nafion117 were filled.Single cell test showed the battery power efficiency was improved by 2.7 %.


Electrodeposition Of Lead Dioxide From Dluoroborate Solutions, Chun-Mei Kong, Yong-Ming Tang, Wen-Zhong Yang, Xiao-Yuan Yang Nov 2010

Electrodeposition Of Lead Dioxide From Dluoroborate Solutions, Chun-Mei Kong, Yong-Ming Tang, Wen-Zhong Yang, Xiao-Yuan Yang

Journal of Electrochemistry

The PbO2 anodes were prepared on platinum from fluoroborate media and its doped solutions by electrodeposition technique.Elecchemical and pysicochemical properties of these PbO2 films were studied by cyclic voltammetry methods,XRD and SEM.The results showed that the presence of BF4-increased PbO2 electrodeposition rate;the prepared lead dioxide consisted of β-PbO2;the preferential orientation of crystals and surface morphology were affected a lot by doping F-and Fe3+.The FB/F-Fe-PbO2 electrode exhibited regular-shaped layers with compact morphology.Furthermore,increasing current density also change the preferential orientation of PbO2 crystals.


Electrochemical Performance Of Zinc Tetra (Trifluoroethoxy) Phthalocyaninate In Aqueous And Nonaqueous Solvents, Xiao-Shan Wu, Li-Ying Huang, Jin-Que Zhang, Shan-Lan Zhu Nov 2010

Electrochemical Performance Of Zinc Tetra (Trifluoroethoxy) Phthalocyaninate In Aqueous And Nonaqueous Solvents, Xiao-Shan Wu, Li-Ying Huang, Jin-Que Zhang, Shan-Lan Zhu

Journal of Electrochemistry

The cyclic voltammetric performance of ZnPcF in N,N-dimethylformaide(DMF),dimethyl sulfoxide(DMSO) solution and phosphate buffer solutions(PBS) has been examined.The results showed that four pairs of redox peaks appeared in nonaqueous solvents,and the values of half-wave redox potential were 0.558 V,-0.761 V,-1.034 V,-1.417 V,respectively,exhibiting four quasi-reversible phthalocyanine ligand based one-electron transfers.In PBS only two redox peaks were observed and the values of half-wave redox potential were-0.885 V,-1.104 V,exhibiting irreversible behavior characteristics.Comparing to the zinc phthalocyanine(unsubstitute ZnPc),introducing electron-withdrawing groups-trifluoroethoxyl to the peripheral sites of the phthalocyanines shifts the redox processes of the complex toward positive potentials.


Eis Study On The Change Of Resistance And Water Absorption During The Failure Graduation Of Inorganic Zinc-Rich/Epoxy/Aliphatic Polyurethane Composite Coatings, Shao-Ping He, Jin-Ping Xiong, Yu-Ming Tang, Yu Zuo Nov 2010

Eis Study On The Change Of Resistance And Water Absorption During The Failure Graduation Of Inorganic Zinc-Rich/Epoxy/Aliphatic Polyurethane Composite Coatings, Shao-Ping He, Jin-Ping Xiong, Yu-Ming Tang, Yu Zuo

Journal of Electrochemistry

The failure process of inorganic zinc-rich/micaceous iron oxide epoxy/aliphatic polyurethane composite coatings in 3.5% NaCl solution under ultraviolet radiation(UV) was studied with Electrochemical Impedance Spectroscopy(EIS).The result shows that the protective property of the coating was enhanced with the increase of total coating thickness,but the degree of improvement reduced gradully as the coating thickness increased.The shielding effect of the micaceous iron oxide epoxy was mainly reflected in the initial period of the service process,while in later period the coating performance largely depended on the zinc-rich primer.The change of the water uptake in the composite coating presented a 'three-stage' characteristic.The thinner the …


Preparation And Characterization Of The Silane-Phosphonic Acid Composite Passivation Coating For Electrogalvanized Steel, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan Nov 2010

Preparation And Characterization Of The Silane-Phosphonic Acid Composite Passivation Coating For Electrogalvanized Steel, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan

Journal of Electrochemistry

A new silane-phosphonic acid composite passivation coating process has been developed for the protection of electrogalvanized steel based on N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane(AAPTMS),γ-(2,3-epoxypropoxy)propyltrimethoxy-silane(GPTMS) and 1-hydroxy ethylidene-1,1-diphosphonic acid(HEDP).The results of X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR),potentiodynamic polarization scan,electrochemical impedance spectroscopy(EIS) and neutral salt spray(NSS) tests indicated that the major structure of the prepared silane-phosphonic acid composite passivation coating consisted mainly of Si—O—Si and Si—O—P bonds.The area of white rust was not more than 5% of the total panal after 120 h NSS test,which could be compared favourably with the chromate colour passivation coating.However,the corrosion reaction on the anode of the silane-phosphonic acid composite passivation …


Study On Preparing Technology And Corrosion Resistance Of Ti/Zr Based Chromium-Free Chemical Conversion Coating On Zinc Electroplating Layer, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan Nov 2010

Study On Preparing Technology And Corrosion Resistance Of Ti/Zr Based Chromium-Free Chemical Conversion Coating On Zinc Electroplating Layer, Yong Guan, Jian-Guo Liu, Chuan-Wei Yan

Journal of Electrochemistry

In this paper,we obtained environmental-friendly chromium-free chemical conversion coating on the non-cyanide alkaline zinc electroplating layer by employing the optimized Ti/Zr based conversion technique.At the same time,the performances of the Ti/Zr based conversion coating were compared with chromate colour passivation coating.The corrosion resistances of the conversion coatings were investigated by using neutral salt spray(NSS) test,potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The results showed that the white rust appeared after 96 hours when the NSS test was performed on the Ti/Zr based conversion coating,which was close to the corrosion resistance rating of chromate colour passivation coating.Compared with the chromate passivation coating,the Ti/Zr …


Comparative Studies On The Deterioration Process Of Organic Coatings Under Immersed And Cyclic Wet-Dry Conditions By Eis, Yu-Nan Li, Jia Wang, Wei Zhang Nov 2010

Comparative Studies On The Deterioration Process Of Organic Coatings Under Immersed And Cyclic Wet-Dry Conditions By Eis, Yu-Nan Li, Jia Wang, Wei Zhang

Journal of Electrochemistry

Under the immersed and wet-dry cyclic conditions,the deterioration processes of the organic coatings on carbon steel surface have been comparatively studied by using electrochemical techniques.The wet-dry cycles were carried out in the alternating conditions of 12 h by immersing in a 3.5% sodium chloride solution and drying at 25 ℃ and 50% RH.Coating resistance,Rf,coating capacitance,Cf,and double layer capacitance,Cd,were monitored continuously and separately under above two conditions.The percentages of the intenfacial active area,Aw,were estimated from the obtained double layer capacitance,Cd.According to the EIS characteristics,the entire deterioration processes under above two mentioned conditions can be divided into three main stages,consisting of the …


Effects Of Solvents And Electrolyte Salts On The Electrochemical Reduction Of Oxygen In Non-Aqueous Electrolytes, Yan-Yan Tian, Wei Wu, Jun Gao, Yong Yang Nov 2010

Effects Of Solvents And Electrolyte Salts On The Electrochemical Reduction Of Oxygen In Non-Aqueous Electrolytes, Yan-Yan Tian, Wei Wu, Jun Gao, Yong Yang

Journal of Electrochemistry

The electrochemical reduction processes of oxygen in different non-aqueous solvents such as acetonitrile(MeCN),propylene carbonate(PC) and their mixtures were investigated by cyclic voltammetry method.The results indicated a one electron reduction of oxygen to O2-occured in these systems as a first step reduction,no matter whether in tetrabutylammonium hexafluorophosphate(TBAPF6)/MeCN or TBAPF6/PC electrolyte.However,the CV curves in 0.1 mol·L-1 TBAPF6/MeCN showed a couple of reversible redox peaks,indicating that the reduction process of oxygen was irreversible in the 0.1 mol·L-1 TBAPF6/PC electrolyte.In the PC-based electrolyte,the reduction current peak reduced largely and the oxidation peak of O2-almost disappeared as compared to that of the former electrolytes.The possible …


Electroless Deposition And Characterization Of Nickel Coating In Lead-And Cadmium-Free Bath, Fang-Zu Yang, Ming-Hui Chen, Xia-Jing Huang, Zhong-Qun Tian, Shao-Min Zhou Nov 2010

Electroless Deposition And Characterization Of Nickel Coating In Lead-And Cadmium-Free Bath, Fang-Zu Yang, Ming-Hui Chen, Xia-Jing Huang, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

Technology of electroless nickel deposition in lead-and cadmium-free bath was developed.Coating′s morphology,composition,structure and electrochemical activity were characterized by SEM,EDS,XRD and electrochemical methods.The results showed that,the deposition rate of nickel in self-catalysing was 22.4 μm·h-1,which was increased by the increase of bath temperature and pH value.The effect of sodium hypophosphite on deposition rate was much more remarkable compared with nickel sulfate.The obtained nickel coating was 7.8% in phosphor weight content,having compact and neat surface morphology,amorphous structure,and good electrochemical corrosion resistance in sodium chloride solution.


Electrochemical Detection For The Corrosion Of Reinforcing Steel In Concrete During Immersion And Drying Cycles, Bing-Li Jia, Fa-He Cao, An-Na Chen, Jian-Qing Zhang Nov 2010

Electrochemical Detection For The Corrosion Of Reinforcing Steel In Concrete During Immersion And Drying Cycles, Bing-Li Jia, Fa-He Cao, An-Na Chen, Jian-Qing Zhang

Journal of Electrochemistry

The corrosion behavior of reinforcing steel in concrete under dry-wet cycle condition has been studied by electrochemical noise(EN) compared with the electrochemical impedance spectroscopy(EIS),SEM micrographs and EDS.The statistical method has been employed to analyze the EN data of reinforcing steel in concrete,which revealed three different corrosion stages of reinforcing steel in concrete,including the dissolution of the passive film,the active corrosion and the cumulation of corrosion product.The wavelet transform has also been employed,which indicated that steel in concrete with pH 1 is associated with uniform corrosion,while steel in concrete with pH 3 and pH 7 are associated with localized corrosion,such as …


Study Of The 11-Ferrocenylalkanethiol Redox-Induced Structure Changes By Flow-Injection Electrochemical Surface Plasmon Resonance, Xiu-Juan Xiao, Yong-Hui He, Juan Xiang, Bin Ren Nov 2010

Study Of The 11-Ferrocenylalkanethiol Redox-Induced Structure Changes By Flow-Injection Electrochemical Surface Plasmon Resonance, Xiu-Juan Xiao, Yong-Hui He, Juan Xiang, Bin Ren

Journal of Electrochemistry

Redox-induced orientation changes of self-assembled monolayers(SAMs) of 11-ferrocenylundecanethiol(FcC11SH) were studied by the flow-injection electrochemical surface plasmon resonance(FI-EC-SPR).Results indicated that there existed two mechanisms concerning the redox-induced structure change of the self-assembled monolayer of ferrocenylalkanethiols:the electrostatic repulsion between the positively charged surface and the ferricenium cation and that among the cations led to a decrease in the tilt angle of the alkanethiol chain;upon Fc oxidation,the Fc group rotated from a tilted conformation to a position where the cyclpentyldiene plane became perpendicular to the electrode.


Study On Aluminum Foils For Aluminum Electrolytic Capacitor, Hui-Zhong Tan, Guo-Qing Qian, Wen-Bao Wang, Lan Sun, Chang-Jian Lin Nov 2010

Study On Aluminum Foils For Aluminum Electrolytic Capacitor, Hui-Zhong Tan, Guo-Qing Qian, Wen-Bao Wang, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Scanning electron microscopy(SEM),X-ray diffraction(XRD),weight-loss method and electrochemical testing method were employed to study the chemical compositions and corrosion behaviors of hard foil and soft foil.The results showed that the surface morphology,chemical composition and crystal structure of hard foil and soft foil are different.It is found from electrochemical tests that the soft foil is suitable to the corrosion under low acidity conditions,which provides the base for developing the corrosion techniques under low acidity conditions.


Electrochemical Behaviors Of Organic Coating/Matal Substrate Under Simulated Deep Sea Environment Partⅰ.Effects Of Seawater Pressure On Transportation Behavior Of Water Through Coating And Coating′S Protective Performance, Bin Liu, Zhi-Gang Fang, Tao Wang, Hong-Bin Wang Nov 2010

Electrochemical Behaviors Of Organic Coating/Matal Substrate Under Simulated Deep Sea Environment Partⅰ.Effects Of Seawater Pressure On Transportation Behavior Of Water Through Coating And Coating′S Protective Performance, Bin Liu, Zhi-Gang Fang, Tao Wang, Hong-Bin Wang

Journal of Electrochemistry

By means of electrochemical impedance spectroscopy(EIS),the electrochemical behaviors of organic coating/metal substrate were studied under simulated deep sea environment in the laboratory.Effects of seawater pressure on the transportation behavior of water through coating and the protective performance of coating were analyzed.The experimental results showed that,compared to normal pressured seawater,there were different impedance characteristics of coating in 3.5 MPa pressured seawater.The main observations were that high seawater pressure accelerated the process of water uptake and invalidation of coating,increased water absorption,and lowered the anti-corrosion property of coating.


Photoelectrochemical Properties Of N,S,And Cl Modified Nano Tio_2 Thin Films, Hong Yun, Chang-Jian Lin, Jing Li, Rong-Gui Du Nov 2010

Photoelectrochemical Properties Of N,S,And Cl Modified Nano Tio_2 Thin Films, Hong Yun, Chang-Jian Lin, Jing Li, Rong-Gui Du

Journal of Electrochemistry

The nitrogen(N),sulfur(S) and chlorine(Cl) modified nano TiO2 thin films were prepared by adding Ti(O-n-Bu)4 as the precursor into concentrated HNO3,H2SO4 and HCl Solutions,respectively,on different substrates in a sol-gel process.The photoelectrochemical performances of N,S and Cl modified nano TiO2 thin films have been studied by UV-vis(DRS),photocurrent curves,EIS and OCP-time curves.N-modified TiO2 nano films show better surface structure,which helps to improve the quantum efficiency of nano TiO2 thin films.


Initial Stage Of Atmospheric Corrosion Of Ndfeb(M35) In A Simulated Marine Atmosphere, Chun-Ling Li, Yuan-Tai Ma, Ying Li, Fu-Hui Wang Nov 2010

Initial Stage Of Atmospheric Corrosion Of Ndfeb(M35) In A Simulated Marine Atmosphere, Chun-Ling Li, Yuan-Tai Ma, Ying Li, Fu-Hui Wang

Journal of Electrochemistry

This study detailed the atmospheric corrosion behaviour of sintered NdFeB(M35) in a simulated marine atmosphere with 80% relative humidity(RH).The dissolution and subsequent reaction of NaCl particles cause the attack of NdFeB.The corrosion presented three representative types:if the electrolyte covered magnetic phase and Nd-rich phase,the Nd-rich phase was corroded firstly due to galvanic effect;if the electrolyte covered magnetic phase,magnetic phase was corroded along the grain boundary;if the electrolyte located near the position of defects,corrosion progressed along with the defect because of low concentration of oxygen inside the defect.With corrosion progressing,local corrosion areas were mutually connected,with Nd-rich phase and grain boundary being …


Hydrothermal Reduction Synthesis Of Lifepo_4 And Its Electrochemical Performance, Hong-Li Zou, Guang-Hui Zhang, Pei-Kang Shen Nov 2010

Hydrothermal Reduction Synthesis Of Lifepo_4 And Its Electrochemical Performance, Hong-Li Zou, Guang-Hui Zhang, Pei-Kang Shen

Journal of Electrochemistry

The cathode materials of LiFePO4 were prepared via a hydrothermal reduction method using FeCl3 as Fe source and iron as a reducing agent.The results showed that ferric salt could be reduced to ferrous salt completely under the hydrothermal condition and pure-phase LiFePO4 was obtained based on the test results of XRD and FTIR.Carbon-coated LiFePO4 was synthesized by pyrolysisng glucose at high temperature.The morphologies of pure LiFePO4 displayed cluster-like while the LiFePO4/C displayed sphere-like particles.The electrochemical test showed that the LiFePO4/C had good rate performance,while LiFePO4 delivered much lower discharge capacity.


Corrosion Electrochemical Behavior Of Am60 Magnesium Alloys In Automobile Engine Coolants, Ling-Jie Li, Sha Wang, Yin Xiao, Jun Lan, Jing-Lei Lei, Sheng-Tao Zhang, Fu-Sheng Pan Nov 2010

Corrosion Electrochemical Behavior Of Am60 Magnesium Alloys In Automobile Engine Coolants, Ling-Jie Li, Sha Wang, Yin Xiao, Jun Lan, Jing-Lei Lei, Sheng-Tao Zhang, Fu-Sheng Pan

Journal of Electrochemistry

The polarization measurements and electrochemical impedance spectroscopy(EIS) were used to study the corrosion electrochemical behavior of AM60 magnesium alloys in three kinds of commercial coolants for automobile engine.Results show that the tested commercial coolants are slightly corrosive to AM60 magnesium alloys and their corrosivity varies from coolant to coolant.The coolant C is the least corrosive among the studied commercial coolants and the coolant A is more corrosive than the coolant B and C.The coolant C appears to be the most promising coolant for automobile engine made by magnesium alloys.The coolant resistivity plays an important role in the corrosion of AM60 …


The Sol-Gel Synthesis And Electrochemical Performance Of Li_3v_2(Po_4)_3/C Cathode Material For Lithium Ion Battery, Li-Ying Liu, Lian Chen, Hai-Yan Zhang, Yu-Chun Zhai Nov 2010

The Sol-Gel Synthesis And Electrochemical Performance Of Li_3v_2(Po_4)_3/C Cathode Material For Lithium Ion Battery, Li-Ying Liu, Lian Chen, Hai-Yan Zhang, Yu-Chun Zhai

Journal of Electrochemistry

Li3V2(PO4)3/C was synthesized by sol-gel method with citric acid as chelate and C sources.Physical and electrochemical performances of as-prepared materials were characterized through XRD,SEM and galvanostatic charge-discharge tests,etc.The results showed that products produced by calcining at 800 ℃ for 12 h had a single phase crystal structure and relatively small particle sizes with uniform distribution.At 0.1 C,0.5 C and 1 C,the initial specific discharge capacities were 153.0,143.1 and 130.6 mAh·g-1,respectively,and capacity efficiencies were 93.1%,85.4% and 77.3% after 50 cycles,respectively.Charge efficiencies were all above 80% and discharge voltages were higher.


Effect Of Cldh On Rebar Corrosion Behavior In Chloride Contaminated Neutral Pore Solutions, Yu-Ming Tang, Le Niu, Yu Zuo Nov 2010

Effect Of Cldh On Rebar Corrosion Behavior In Chloride Contaminated Neutral Pore Solutions, Yu-Ming Tang, Le Niu, Yu Zuo

Journal of Electrochemistry

The effect of calcined LDH-MgAl-CO3 on rebar corrosion behavior in chloride ion contaminated neutral concrete pore solutions was investigated in this paper.Corrosion potentials of rebars in pore solutions after treatment with CLDH were higher than before treatment.According to polarization tests,passivated region of rebars in pore solutions after treatment with CLDH was found apparently instead of activation.EIS tests showed that CLDH made the impedance of specimens increase.The measurements of pH and chloride ion concentration after treatment indicated that / of pore solutions decreased by 4~5 magnitude orders.


Electrooxidation Of Carbon Monoxide On Pd Thin Film-Coated Au Electrodes:Film Thickness Dependence, Yuqing Yang, Shouzhong Zou Aug 2010

Electrooxidation Of Carbon Monoxide On Pd Thin Film-Coated Au Electrodes:Film Thickness Dependence, Yuqing Yang, Shouzhong Zou

Journal of Electrochemistry

The adsorption and electrooxidation of CO on Pd-coated Au electrodes were studied by cyclic voltammetry and surface-enhanced Raman spectroscopy (SERS) . It is found that CO oxidation activity is film thickness dependent. Cyclic voltammograms (CVs) showed that CO oxidation peak potential shifted positively with the increase of the Pd thickness. SERS showed a redshift of the C—O stretching frequency with increasing Pd film thickness. These observations were explained by the dband theory. The strain effect strengthens CO adsorption and stabilizes adsorbed CO,while the ligand effect weakens CO adsorption and eases its oxidation. The ligand effect overpowers the strain effect.


The Mechanism Of ~(13)Co_(Ad)/~(12)Co Isotope Exchange At Pt Electrode,A Combined Study By Electrochemical In-Situ Infrared Spectroscopy And Dipole-Dipole Coupling Analysis, Sang-Zi Liang, Shao-Xiong Liu, Ling-Wen Liao, Qian Tao, Jing Kang, Yan-Xia Chen Aug 2010

The Mechanism Of ~(13)Co_(Ad)/~(12)Co Isotope Exchange At Pt Electrode,A Combined Study By Electrochemical In-Situ Infrared Spectroscopy And Dipole-Dipole Coupling Analysis, Sang-Zi Liang, Shao-Xiong Liu, Ling-Wen Liao, Qian Tao, Jing Kang, Yan-Xia Chen

Journal of Electrochemistry

In this contribution,we have analyzed the IR spectra of saturated CO adlayer at rough Pt film electrode as a function of fractional surface coverage of 13COad/12COad recorded during 13COad /12CO isotope exchange process according to dipole-dipole coupling theory and coherent potential approximation. By properly choosing the parameters of adlayer structure and dipole-dipole coupling interaction under coherent potential approximation, we demonstrated that we can successfully simulate the IR spectra as a function of the surface coverage of CO adlayer at rough Pt film electrodes by assuming that COad molecules with low C—O stretching frequencies are dis- placed preferentially during the 13COad/12CO …


Preliminary Investigation Of Iron Protoporphyrin Sams On Platinum Electrodes By Surface Enhanced Vibrational Spectroscopies, Min Ma, Yao-Yue Yang, Han-Xuan Zhang, Wen-Bin Cai Aug 2010

Preliminary Investigation Of Iron Protoporphyrin Sams On Platinum Electrodes By Surface Enhanced Vibrational Spectroscopies, Min Ma, Yao-Yue Yang, Han-Xuan Zhang, Wen-Bin Cai

Journal of Electrochemistry

In situ SERS and ATR-SEIRAS were applied to investigate the electrochemical and structural properties of iron protoporphyrin IX (FePP) self-assembled monolayers (SAMs) on Pt electrodes in 0. 1 mol· L -1 HClO4. The potential dependent SERS spectra of the FePP SAM on a roughened Pt electrode with the enhancement factor of ca. 40 were acquired with the excitation line of 514 nm. Analyses of SERS data over the potential region from 0. 5 to -0. 3 V enabled to obtain potential dependent adsorption isotherms,from which the formal redox potential could be estimated to be ca. - 0. 2 V. Up-tilted …


Multi-Electron Redox Materials For High Energy Density Electrodes, Xin-Ping Ai, Han-Xi Yang Aug 2010

Multi-Electron Redox Materials For High Energy Density Electrodes, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

Various new energy technologies being developed require electrochemical energy batteries to have a real breakthrough in energy density and rate capability,which imposes a great challenge for electrochemists and materials chemists. Multi-electron redox reactions seem to open a promising avenue to create new batteries with dramatically enhanced energy densities. This paper describes simply our research works on the multi-electron redox systems,including metal boride anode,lithium alloying compounds and electrochemical conversion materials, and also discusses the problems hindering these systems for battery applications.


In Situ Surface-Enhanced Raman Scattering Spectroscopic Study Of Sulfur Adsorption On Polycrystalline Platinum Electrode Surface, Bolian Xu-, In-Su Park, Ying Li, De-Jun Chen, Yuye J. Tong Aug 2010

In Situ Surface-Enhanced Raman Scattering Spectroscopic Study Of Sulfur Adsorption On Polycrystalline Platinum Electrode Surface, Bolian Xu-, In-Su Park, Ying Li, De-Jun Chen, Yuye J. Tong

Journal of Electrochemistry

The paper reports the first in situ surface enhanced Raman scattering (SERS) spectroelectrochemistry study of sulfur adsorption and electro-oxidation on highly roughened polycrystalline Pt surface in both acidic and basic supporting electrolytes. The SERS spectra were taken at a constant electrode potential after accumulative electro-oxidation CVs of the Pt electrode with pre-adsorbed sulfur species and at different electrode potentials that were varied stepwise of the Pt electrode immersed in sulfur-containing electrolytes without pre-adsorbed sulfur species. In both cases,a dominant vibrational band at 299 cm -1 in acidic electrolyte but at 310 cm-1 in basic electrolyte was observed,which was assigned to …


Solid State Nmr Studies Of Lithium Manganese Silicate As Positive Electrode Materials For Li-Ion Batteries, Hu Cheng, Zi-Geng Liu, Yi-Xiao Li, Zhong Chen, Yong Yang Aug 2010

Solid State Nmr Studies Of Lithium Manganese Silicate As Positive Electrode Materials For Li-Ion Batteries, Hu Cheng, Zi-Geng Liu, Yi-Xiao Li, Zhong Chen, Yong Yang

Journal of Electrochemistry

The Li2MnSiO4 cathode material for lithium ion batteries was synthesized by sol-gel assisted hydrothermal method. XRD,FTIR and SS-NMR were used to study the phase,structure and morphology of obtained samples. Electrochemical performance of cathode material was tested. The results show that the main phase of sample prepared was Li2MnSiO4,whereas a small amount of impurities ( Li2CO3) were existed. The Li2MnSiO4 cathode material gave an initial discharging capacity of about 190 mAh·g -1. But this capacity faded rapidly during the cycling process due to the decomposition of Li2MnSiO4.


Density Functional Theory Studies Of Surface-Enhanced Raman Spectroscopy In Electrochemical Interfaces, Liu-Bin Zhao, De-Yin Wu, Bin Ren, Zhong-Qun Tian Aug 2010

Density Functional Theory Studies Of Surface-Enhanced Raman Spectroscopy In Electrochemical Interfaces, Liu-Bin Zhao, De-Yin Wu, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Quantum chemical density functional theory and Raman scattering theory were used to study the bonding mechanism and surface-enhanced Raman spectroscopy of pyridine adsorbed on transition metals (Ⅷ group) and coinage metals (IB group) . SERS studies of pyridine-metal systems have been reviewed. Chemical bonding mechanism as well as photo-driven charge transfer mechanism was considered to investigate the vibrational frequency shift and the enhancement of SERS intensity in electrochemical interfaces. Our theoretical results can be used to interpret the SERS phenomena dependent on metals,excitation wavelengths,and applied potentials.


Comparative Study Of Nanoporous Pt,Ptru And Ptruir Catalysts Using Electrochemical Ftir Spectroscopy, M. Amussen Robert, Holt-Hindle Peter, Nigro Samantha, Chen Aicheng Aug 2010

Comparative Study Of Nanoporous Pt,Ptru And Ptruir Catalysts Using Electrochemical Ftir Spectroscopy, M. Amussen Robert, Holt-Hindle Peter, Nigro Samantha, Chen Aicheng

Journal of Electrochemistry

In recent years much effort has been put towards developing efficient Pt-based electrocatalysts for applications in fuel cells. With the rising cost of precious metals such as Pt,the need to enhance the activity and to decrease the load of catalysts is prominent. Herein we report on the synthesis and comparative study of nanoporous Pt,PtRu and PtRuIr electrocatalysts. The nanoporous electrodes were fabricated using a hydrothermal method and characterized by scanning electron microscopy (SEM) ,energy dispersive spectroscopy (EDS) ,X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) . The electrocatalytic activity of the fabricated nanopo- rous materials was evaluated using both CO …


The Sers Effect Of Au_(Core)@Pt_(Shell) Nanoparticles With Different Pt Shell Thicknesses, Yan Zhong, Liang-Liang Yan, Gui-Shi Rao, Xiao-Cong Deng, Fei-Peng Wen, Jin-Long Xu, Qi-Ling Zhong Aug 2010

The Sers Effect Of Au_(Core)@Pt_(Shell) Nanoparticles With Different Pt Shell Thicknesses, Yan Zhong, Liang-Liang Yan, Gui-Shi Rao, Xiao-Cong Deng, Fei-Peng Wen, Jin-Long Xu, Qi-Ling Zhong

Journal of Electrochemistry

By using Au nanoparticles with a diameter of 55 nm as the core and ascorbic acid as the reductant, Aucore@ Ptshell nanoparticles of controllable Pt shell thickness( 0. 3 ~ 6 nm) were synthesized by controlling the concentration of [PtCl6]2 - ions. The ultraviolet-visible absorption spectrometry,scanning electron microscope ( SEM) ,transmission electron microscope ( TEM) ,high resolution transmission electron microscope ( HRTEM) , and electrochemical cyclic voltammetry were employed to determine surface morphology and structure of Aucore@ Ptshell. With SCN - ion as a probe,the effect of the thickness of the Pt shell on the SERS signals of Aucore@ Ptshell …


Phenomena Characterization Of Energy Materials By X-Ray Absorption Spectroscopy, Ming-Yao Cheng, Chun-Jen Pan, Ju-Hsiang Cheng, Bing-Joe Hwang Aug 2010

Phenomena Characterization Of Energy Materials By X-Ray Absorption Spectroscopy, Ming-Yao Cheng, Chun-Jen Pan, Ju-Hsiang Cheng, Bing-Joe Hwang

Journal of Electrochemistry

The aim of this review is to introduce the characterization of energy materials by X-ray absorption spectroscopy (XAS) . This technique allows us to probe changes in the valance state and the local environment of the targeted element in the active material; thereby,leading to a better understanding of its electrochemical behavior,and hopefully showing the way to improved performance. Here,electrocatalysts for fuel cells and active electrode materials for Li-ion batteries are taken as the examples that illustrate the capability of XAS and allow observation and theory to be correlated with electrochemical phenomena.