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2004

Chemistry

Articles 31 - 51 of 51

Full-Text Articles in Engineering Science and Materials

Stability And Electrochemical Performance Of Nio Cathode Modified By Zno Additive For Mcfc In Molten Carbonates, Huang Bo May 2004

Stability And Electrochemical Performance Of Nio Cathode Modified By Zno Additive For Mcfc In Molten Carbonates, Huang Bo

Journal of Electrochemistry

The ZnO/Ni composite cathode was fabricated by tape-casting method, which microstructures and phases were studied. The electrochemical behaviors of ZnO impregnated NiO cathodes were also evaluated in molten 62 mol%Li_2CO_3+(38 mol%) K_2CO_3eutectic at 650 ℃ by electrochemical impedance spectroscopy (EIS) as a function of ZnO content and immersion time. The ZnO impregnated nickel cathodes showed the similar porosity, pore size and morphology to the reference nickel cathode. The stability tests of ZnO impregnated NiO cathodes showed that the ZnO additive could dramatically reduce the solubility of NiO in a eutectic carbonate mixture under the standard cathode gas condition. The cathode …

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Study On Electrochemical Performance Of Electroless Cobalt Coating For Microencapsution Of Hydrogen Storage Alloys, Tong-Chi Xia, Sheng-Li Zhang, Shu-Xin Wang, Kun Huang, Wen-Zeng Tian May 2004

Study On Electrochemical Performance Of Electroless Cobalt Coating For Microencapsution Of Hydrogen Storage Alloys, Tong-Chi Xia, Sheng-Li Zhang, Shu-Xin Wang, Kun Huang, Wen-Zeng Tian

Journal of Electrochemistry

The chemical cobalt plating method is used to treat on the hydrogen storage alloys.Effect of the surface treatment on the electrochemical performance of MH eletrodes was investigated by carrying out experimental methods of CV,AC and charge/discharge cycle tests. The results showed that after microencapsulation with cobalt, the impedance of electrochemical reaction on the surface and polarization during chare/discharge process was markedly decreased; and the electrocatalytic activity on the surface, discharge capacity,charge efficiency was improved. It was also indicated that the anode reaction of MH electrode treated was controlled by diffusion process.

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Investigation Of Adsorption And Oxidation Behavior Of Isosafrole On A Smooth Pt, Xiao-Hong Zhang May 2004

Investigation Of Adsorption And Oxidation Behavior Of Isosafrole On A Smooth Pt, Xiao-Hong Zhang

Journal of Electrochemistry

The electro-oxidation of isosafrole on a smooth platinum electrode was investigated in the non-aqueous solution. The CV curve shows two oxidation peaks and one reduction peak in the potential region between -0.5 V and 1.95 V. The relation between the oxidation and reduction peaks has been determined also by CV. The adsorption behavior of isosafrole on Pt was also investigated.

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Study On Reduction Process Of Electrolyic Manganese Dioxide In Situ By Ultraviolet-Visible Absorption Spectroscopy, Li-Cai Zhu, Zhong-Zhi Yuan, Wei-Shan Li May 2004

Study On Reduction Process Of Electrolyic Manganese Dioxide In Situ By Ultraviolet-Visible Absorption Spectroscopy, Li-Cai Zhu, Zhong-Zhi Yuan, Wei-Shan Li

Journal of Electrochemistry

The concentrationsof soluble Mn(Ⅲ) species,during the reduction ofelectrolytic MnO_(2) (EMD)in alkaline solution,have been monitored in situ by UV-visible spectroscopy. The concentration of Mn(Ⅲ) ion in solution changes with discharge time.The first electron discharge process of EMD can be described by three different steps: 1) the reduction of Mn~(4+)ions on the surface of EMD particles and the structural defect regions within the EMD,2) the reduction of Mn~(4+)ions in ramsdellite,3)the reduction of Mn~(4+)ions in pyrolusite. During the second electron discharge of EMD, the soluble Mn(Ⅲ) is reduced to Mn(Ⅱ) , then Mn(OH)_(2)and Mn_(3)O_(4)are formed.

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Study Of Anti-Corrosion Property On Poly(An-Co-Oas)/Epoxy, Qing-Wu Wang, Geng-Chao Wang May 2004

Study Of Anti-Corrosion Property On Poly(An-Co-Oas)/Epoxy, Qing-Wu Wang, Geng-Chao Wang

Journal of Electrochemistry

polyaniline, polyanisidine and their copolymer poly(An-co-oAs) were synthesized via the solution chemical oxidative polymerization of aniline and anisidine in an acidic aqueous medium, and their properties and structure were characterized. The electrochemical method were applied to evaluate the corrosion behavior of tined iron uncoated or coated by polyaniline, poly(An-o-oAs), polyanisidine and poly(An-co-oAs)/epoxy blend in acid or saline aqueous solution. The result showed that with the increase of anisidine content, the solubility of polymers is improved apparently but their oxidation extent decreases accordingly. It is also founded that polyaniline, poly(An-co-oAs) and polyanisidine all have good anti-corrosion properties, and their anti-corrosion capacity …

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Electrocatalytic And Lifetime Studies Of Commercial Catalystsin A Pemfc, Cheng Xuan May 2004

Electrocatalytic And Lifetime Studies Of Commercial Catalystsin A Pemfc, Cheng Xuan

Journal of Electrochemistry

A particularly designed H-type cell was used to simulate the operating condition of a hydrogen-air proton exchange membrane fuel cell (PEMFC). The electrocatalytic activity, morphology, structure and lifetime of commercially available catalysts, carbon support platinum (Pt/C) and unsupported platinum-ruthenium (Pt-Ru), were preliminary studied by carrying out electrochemical measurements and by SEM, XRD techniques. The catalysts were simultaneously tested in the H-cell under operation, and also separately tested in a conventional electrochemical cell for comparison. It was found that the characteristic peaks of hydrogen adsorption/desorption on cyclic voltammograms shifted considerably to a more positive direction for Pt/C, while a more negative …

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Preparation, Characterization And Photoelectrochemical Activities Of Cu-Tio_2/Ito Films, Dong Shu May 2004

Preparation, Characterization And Photoelectrochemical Activities Of Cu-Tio_2/Ito Films, Dong Shu

Journal of Electrochemistry

Cu-TiO_(2)/ITO films were prepared by direct photo-reduction deposition of Cu~(2+) on TiO_(2)/ITO films. The nanocomposite films were characterized by UV-vis diffuse reflectance spectra (DRS), XRD spectra, Scanning Electron Microscope (SEM) technology, and photovoltage measurement. The feasibility of improving the photocatalytic activity of TiO_(2) film by combining the modification of Cu nanoparticles with the application of anodic bias was investigated. The experimental results showed that the deposited Cu has an apparent enhancement effect with respect to suppressing the recombination between the photogenerated charge carriers and enhancing the photocatalytic oxidation of formic acid. The combination could promote the photocatalytic oxidation of formic …

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Electrodeposition Of Copper Into Trenches Under Rotating Hydrodynamic Condition, Jian-Jun Sun May 2004

Electrodeposition Of Copper Into Trenches Under Rotating Hydrodynamic Condition, Jian-Jun Sun

Journal of Electrochemistry

Silicon chips patterned with treneches were fixed onto a rotating electrode. Copper was electrodeposited into the trenches under rotating hydrodynamic conditions The sizes of the trenches are 1 m in height and 0.35 m, 0.50 m and 0.70 m in width, respectively. The effects of rotating of the chip, the current density and the concentration of Cu~(2+ )on the filling of thetrenches were studied. It is found that lower current density and moderate concentration of Cu~(2+)resulted in a void free filling of the trenches.

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Exceptional Electrochemical Activities Of Amorphous Fe-B And Co-B Alloy Particles Used As High Capacity Anode Materials, Ya-Dong Wang, Xin-Ping Ai, Han-Xi Yang May 2004

Exceptional Electrochemical Activities Of Amorphous Fe-B And Co-B Alloy Particles Used As High Capacity Anode Materials, Ya-Dong Wang, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

Ultrafine amorphous alloy particles (UAAP) of Fe-B and Co-B were synthesized and tested for possible use as electroactive anode materials. It is found that unlike their parent elements, the alloy particles of transition metal (TM) and boron, the Fe-B and Co-B showed superior electrochemical activities when used as anodic materials in aqueous alkaline solution. The discharge capacities of Fe-B and Co-B electrodeswere observed to be 1 200 mAh/gand 1 100 mAh/gat moderately high rate of 100 mAh/g, respectively, much higher than the theoreticalcapacity of currently used zinc metal (820 mAh/g). The exceptional high capacities of the boride alloys were probably …

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Substrates Made By Electrodeposition For Measuring Electrical Properties Of One Dimensional Nanomaterials, Jin-Xuan Liu, Juan Xiang, Zhong-Qun Tian, Bing-Wei Xiamen University Mao, Xiamen Xiamen, China China Feb 2004

Substrates Made By Electrodeposition For Measuring Electrical Properties Of One Dimensional Nanomaterials, Jin-Xuan Liu, Juan Xiang, Zhong-Qun Tian, Bing-Wei Xiamen University Mao, Xiamen Xiamen, China China

Journal of Electrochemistry

A method to prepare alternating conducting/insulating substrates by electrodeposition-oxidation was established to facilitate I-E measurements of one-dimensional nanomaterial by CT-AFM. The prepared Au/CuO and HOPG/CuO substrates showed low roughness as well as high uniformity of the alternating conducting/insulating structure, Qualitative I-E measurements were performed on a single carbon nanotube attached to the two above-mentioned substrates, both showing metallic characteristics at room temperature and in air.

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Progress In Research For Biofuel Cell, Yue Bao, Xia-Qin Wu Feb 2004

Progress In Research For Biofuel Cell, Yue Bao, Xia-Qin Wu

Journal of Electrochemistry

In this article, research progresses of the biofuel cell in recent years were summarized. The operation principle and classification of the biofuel cells were described. The role of the mediator for promoting electron transfer in biofuel cells and the techniques for improving the electric properties of biofuel cells, such as output potential, were discussed with some attracting research instances. Finally, the choke points for research of biofuel cell were explored, and the application prospect of biofuel cells was forecasted.

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Preparation, Structure And Electrochemical Hydrogenation Of Carbon Nanotubes Supported Platinum Catalysts, Qing-Gang He, Xiao-Zi Yuan, Xian-Xia Yuan, Zi-Feng Ma Feb 2004

Preparation, Structure And Electrochemical Hydrogenation Of Carbon Nanotubes Supported Platinum Catalysts, Qing-Gang He, Xiao-Zi Yuan, Xian-Xia Yuan, Zi-Feng Ma

Journal of Electrochemistry

In this paper, Pt/CNTs catalyst was prepared and its electrocatalytic property was studied by obtaining cycling voltammetry curves (C-V) and Tafel curves. In addition, the XRD,XPS and TEM tests were carried out to determine the structure and composition of the catalysts. It can be found that the platinum loading has been increased significantly using a carbon nanotubes support. Dispersion of Platinum was better and gave more active sites. The electrochemical characteristic of Pt/CNTs was also more desirable than that of Pt/C catalyst(Johnson Matthey). In conclusion, carbon nanotubes can played a conspicuous role in "electrogenerative" processes of PEMFC hydrogenation reactor.

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Study Of Electrochemical Properties Of The Hydride Alloy Electrode Zrcr_(0.4)Mn_(0.2)V_(0.1)Co_(0.1)Ni_(1.2) At High Temperature, Song Li, Shi-Jun Ji, Jun-Cai Sun Feb 2004

Study Of Electrochemical Properties Of The Hydride Alloy Electrode Zrcr_(0.4)Mn_(0.2)V_(0.1)Co_(0.1)Ni_(1.2) At High Temperature, Song Li, Shi-Jun Ji, Jun-Cai Sun

Journal of Electrochemistry

Electrochemical properties of the hydride alloy electrode ZrCr_(0.4)Mn_(0.2)V_(0.1)Co_(0.1)Ni_(1.2) at the different temperature have been investigated. The results showed that the alloy electrodes possessed the maximum discharge capacities 336 mAh/g and 298 mAh/g at 25 ℃ and 70 ℃ respectively. The activation process of the alloy at 70 ℃ became faster, and the alloy reached its maximum capacity in less than 4 cycles, while in 13 cycles at 25 ℃. The high rate capability increased from 55 % at 25 ℃ to 71% at 70 ℃ at 300 mA/g. It was worth noting that the alloys at 25 ℃ and 70 …

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Study On Determination Of Iodine Ion At Chitosan Modified Glassy Carbon Electrode, Bin Liu, Xiang-Ying Sun, Jin-Rui Xu Feb 2004

Study On Determination Of Iodine Ion At Chitosan Modified Glassy Carbon Electrode, Bin Liu, Xiang-Ying Sun, Jin-Rui Xu

Journal of Electrochemistry

In this paper, a chitosan modified glassy carbon electrode was prepared by the method of covalent-bond reaction, and the anodic stripping voltammetric characteristics of iodine on the modified electrode was studied. The results showed that the modified electrode has higher adsorption and selectivity for I~-, and the sensitivity for I~- has been much improved in 0.1 mol·L~(-1) KH_2PO_4 solution (pH=4.0). The anodic stripping peak current of I~- on the modified electrode varied linearly with I~- concentration in the range of 2.0×10~(-6)～2.0×10~(-3) mol·L~(-1), and the detection limit reached 2.0×10~(-7) mol·L~(-1).

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The Interaction In Doping Lithium Of Carbonaneous Anode In Lithium Ion Battery, Chang-Guo Chen, Hong-Min Zhang, Jia Chen, Dan-Mei Yu Feb 2004

The Interaction In Doping Lithium Of Carbonaneous Anode In Lithium Ion Battery, Chang-Guo Chen, Hong-Min Zhang, Jia Chen, Dan-Mei Yu

Journal of Electrochemistry

The quantum chemical DV-X_α method was used to calculate the lithium-doped models from one-Li-dopant to LiC_6 and LiC_2. It was found that Li~+ has an tendency to attract electrons from the carbon plane through the C_6 hexagons lying above or below it by the graph of charge-density difference. It was shown that LiC_6 can exist steadily,while LiC_2 can not exist steadily.

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Template Synthesis Of Highly Ordered Monocrystalline Metal Nanowire Arrays By A Two-Step Ac Electrodeposition, Juan Xiang, Jing-Hua Tian, Zi-Mian Ni, Zhi-Feng Huang, Bo Liu, Zhong-Qun Tian Feb 2004

Template Synthesis Of Highly Ordered Monocrystalline Metal Nanowire Arrays By A Two-Step Ac Electrodeposition, Juan Xiang, Jing-Hua Tian, Zi-Mian Ni, Zhi-Feng Huang, Bo Liu, Zhong-Qun Tian

Journal of Electrochemistry

The monocrystalline metal nanowire arrays were prepared by using a two-step AC electrodeposition in porous anodic aluminum oxide (AAO) template. The growth mechanism of nanowires was discussed. As a result, it has been found that the second voltage pulse has a considerable effect on the pore-filling ratio, the uniformity and the crystal structure, whereas the initial voltage pulse affects only the pore-filling ratio. Using the two-step AC electrodeposition, a highly ordered monocrystalline metal nanowire arrays with a pore-filling ration above 95% can be easily obtained.

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Electrochemical Character Of Water Containing Gel Electrolyte And Its Preliminary Examination In Lithium Water Cell, Jing-Dong Liu, Wen-Ji Wang, Xin-Zheng Yi Feb 2004

Electrochemical Character Of Water Containing Gel Electrolyte And Its Preliminary Examination In Lithium Water Cell, Jing-Dong Liu, Wen-Ji Wang, Xin-Zheng Yi

Journal of Electrochemistry

AC impedance technique has been used to characterize the system of poly(methyl acrylic acid )-poly(methyl acrylic lithiumate )-glycerol (referred to as GPE ) .The results showed that the conductivity of GPE increased with increasing both temperature and its water content .The glass transition temperature of GPE polymer could be lowered by water .Its conducting characteristic was just like liquid electrolyte ,The electrolysis of GPE was almost the same as the electrolysis of water .Its composition voltage was about 1.50V .The GPE has been used to manufacture lithium water cell. When the graphite was used as cathode, the cell could discharge …

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Studies On The Mechanism Of Electroreduction Of Oxalic Acid, Yu Zhan Li, Xin Liu, Rui Sheng Hu, Deng Ping Gu Feb 2004

Studies On The Mechanism Of Electroreduction Of Oxalic Acid, Yu Zhan Li, Xin Liu, Rui Sheng Hu, Deng Ping Gu

Journal of Electrochemistry

The electroreduction mechanism of oxalic acid on Pb electrode in Na_2SO_4 solution were investigated using high scan rate cyclic voltammetry and chronoamperometry. The dynamic parameters for the first step electron transter reaction of oxalic acid electroreduction by were determined. The corresponding reduction peak potentials of oxalic acid, glyoxylic acid and glycolic acid in the cyclic voltammogranis obtained in the same condition were compared, and the intermediate reduction products of oxalic acid were suggested. The results showed that oxalic acid is weakly absorbed on the lead electrode.

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Formation And Characterization Of Water-Repellent Nano Tio_2 Coating And Studying Its Anticorrosion Property, Guang-Xia Shen, Yi-Cong Chen, Chang-Jian Lin Feb 2004

Formation And Characterization Of Water-Repellent Nano Tio_2 Coating And Studying Its Anticorrosion Property, Guang-Xia Shen, Yi-Cong Chen, Chang-Jian Lin

Journal of Electrochemistry

Using ethyl acetoacetate (EAcAc) as a chelating agent, ultra fine TiO_2 sol is prepared. Nano-TiO_2 coatings are deposited on the 316L stainless steel by the dip-coating. Hydrothermal post-treatment leads to crack-free coatings. Meanwhile, the surface struture and properties was optimized. Self-assembly of Hetadecafluorodecyltrimethoxysilane (FSA-13) fabricates hydrophobic layers on the surface of the nano-TiO_2 coatings. Particle sizes of TiO_2 sol was analysed by zeta pals potential analysis, and surface morphology, structure and properties was characterized by contract angle instrument, XRD, and SEM technologies. The results have shown that the surface of coatings is porous, with approx. 375 nm thick, the particle …

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Electrochemical Synthesis Of Ferrate(Vi) By Anodic Oxidation, Jia-Ju Xu, Jian-Ming Wang, Wei-Hua Yang, Cheng Chen, Jian-Qing Zhang Feb 2004

Electrochemical Synthesis Of Ferrate(Vi) By Anodic Oxidation, Jia-Ju Xu, Jian-Ming Wang, Wei-Hua Yang, Cheng Chen, Jian-Qing Zhang

Journal of Electrochemistry

The ferrate(Ⅵ) was synthesized by electrochemical anodic oxidation. The effects of preparation conditions on the current yield of ferrate(VI) synthesis have been studied in this work. The experimental results showed that grey cast iron as an anodic material is suitable for electrochemical synthesis and NaOH solution as an electrolyte results in a higher current yield than KOH solution. The highest current yield was obtained at a current density (4.54) mA· cm~(-2),temperature 20　℃ and 14 mol·dm~(-3) NaOH. In this case, a current yield of 68.5% was obtained by electrolysis for 1 h.

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Electrodeposition Nanolaminated Growth Of Zinc, Ying Cao, Tian-Hui Shen, Jing-Yuan Yao, Gui-Fu Ding Feb 2004

Electrodeposition Nanolaminated Growth Of Zinc, Ying Cao, Tian-Hui Shen, Jing-Yuan Yao, Gui-Fu Ding

Journal of Electrochemistry

Nanolaminated growth of the electrodeposition of zinc was studied. The structure and size of crystalline in zinc coatings were investigated by using FEG-TEM and XRD. The corrosion tests of the zinc deposition and the Coatings-Neutral salt spray test were performed, the capability in corrosion resistance of the nanolaminated growth was better than that of others.

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