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2004

Articles 1 - 23 of 23

Full-Text Articles in Catalysis and Reaction Engineering

Electrochemical Behaviours Of Hemoglobin-Ddab-Modified Powder Microelectrode And The Application Of The Powder Microelectrode In Determination Of Nitric Oxide, Zhi-Mou Guo, Huan Liu, Jian Chen, Wen-Ting Zhang Nov 2004

Electrochemical Behaviours Of Hemoglobin-Ddab-Modified Powder Microelectrode And The Application Of The Powder Microelectrode In Determination Of Nitric Oxide, Zhi-Mou Guo, Huan Liu, Jian Chen, Wen-Ting Zhang

Journal of Electrochemistry

The electrochemical behaviours of DDAB-Hb-PME were studied in this paper. The (apparent) surface concentration of Hb was enhanced greatly by using the powder microelectrode (technique). NO reacts with Hb and absorbs on the surface of the modified carbon powder. Therefore, the output of the electrode was enhanced greatly by employing PME with higher reaction surface (area). The sensitivity of DDAB-Hb-PME is 3.1 mA/μmol·L~(-1)·cm~(2), which is much larger than the values obtained with the traditional electrodes. The detection limit is 9 nmol·L~(-1) and the linear response range is 9～100 nmol·L~(-1).

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Electrocatalytic Performances Of Carbon Nanotube Air Electrode For Oxygen Reduction, Feng-Ming Zhao, Chun-An Ma Nov 2004

Electrocatalytic Performances Of Carbon Nanotube Air Electrode For Oxygen Reduction, Feng-Ming Zhao, Chun-An Ma

Journal of Electrochemistry

The air electrodes with different mass ratio of Pt/active carbon or carbon nanotube as catalyst layer material have been prepared. The electrocatalytic performances for oxygen reduction were evaluated by means of polarization curve and electrochemical impedance spectroscopy (EIS). The results disclosed that carbon nanotubes dealt with nitric acid in the catalyst layer had been improved obviously on the electrocatalytic activity. After the surface of carbon nanotube was oxygenated and aggraded with platinum, the catalyst had obviously effects on the electrocatalytic activity. The air electrode with the mass ratio of active carbon to Pt/carbon nanotube in 4∶1 showed better electrocatalytic activity, …

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Anodic Dissolution Of Aluminum In Koh-Ethanol Solutions, Hai-Bo Shao, Jian-Ming Wang, Xiao-Yan Wang, Yi Zheng, Jian-Qing Zhang Nov 2004

Anodic Dissolution Of Aluminum In Koh-Ethanol Solutions, Hai-Bo Shao, Jian-Ming Wang, Xiao-Yan Wang, Yi Zheng, Jian-Qing Zhang

Journal of Electrochemistry

The feasibility of employing aluminum in KOH ethanol solution as a battery anode system was discussed. Weight loss measurement showed that the corrosion rate of Al is low enough to be used in sealed batteries. Through the measurements done by anodic polarization, EIS and galvanostatic discharge, it was found that A1 is electrochemical active in a wide potential range in this system, and its discharge mechanism is similar to that of A1 in aqueous solution. The discharge potential increased rapidly after a period of time, which might be caused by the discharge products depositing on the electrode surface.

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Preparation And Photo-Catalyst Properties Of The Α-Fe_2o_3-Tio_2 Films On Sodium Alginate Polymer, Li-Qin Chen, Huai-Zhen Zhong, Ri-Yao Chen, Xi Zheng, Zhen Chen Nov 2004

Preparation And Photo-Catalyst Properties Of The Α-Fe_2o_3-Tio_2 Films On Sodium Alginate Polymer, Li-Qin Chen, Huai-Zhen Zhong, Ri-Yao Chen, Xi Zheng, Zhen Chen

Journal of Electrochemistry

Three new nano thin films of α-Fe_2O_(3)、TiO_2 and α-Fe_2O_(3)-TiO_2 by doping their powder with sodium alginate polymer were prepared. Surface structure and catalytic activities of the films were characterized by FTIR、XRD、PL、TEM and I-V techniques. The results of UV-visible absorption showed that the methylene blue was mineralized in aqueous of α-Fe_2O_(3)/SA、TiO_2/SA and (α-(Fe_2O_(3)))-TiO_2 /SA upon radiation with ultra violet light. α-Fe_2O_(3) enhanced their photo-decolorized-activities by doping 15% TiO_2.

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Effect Of Fe~(3+) Dopen Of Titanium Dioxide Film On Absorption Spectra And Photo Catalysis, Mei-Qun Xiao, Jia-Nian Shen, Moucheng Li, Peng-Fei Wu, Dong Liu, Yu-Juan Zhang Nov 2004

Effect Of Fe~(3+) Dopen Of Titanium Dioxide Film On Absorption Spectra And Photo Catalysis, Mei-Qun Xiao, Jia-Nian Shen, Moucheng Li, Peng-Fei Wu, Dong Liu, Yu-Juan Zhang

Journal of Electrochemistry

Photo-catalytic titanium dioxide film in nano crystalline has been prepared by electrochemical oxidation process and adding different amount of ferric ion into the electrolyte during the anodic oxidation.The effects of Fe~(3+) dopen on absorption spectra and photo-catalytic of the titanium dioxide films have been studied. It shows that the Fe~(3+) dopen caused the red shife of the absorption edge for the incoming light and exhibited the improved photocatalytic reactivity.

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Solid State Synthesis And Electrocatalysis Of Pt/Moo_3 For The Oxidation Of Methanol, Wang Qing Aug 2004

Solid State Synthesis And Electrocatalysis Of Pt/Moo_3 For The Oxidation Of Methanol, Wang Qing

Journal of Electrochemistry

The electrocatalyst, Pt/MoO_(3) synthesized by solid state reaction, was used for the oxidation of methanol in direct methanol fuel cells. The X-Ray diffraction and cyclic voltammetry were employed to investigate the performance of the material. It was shown that the typical diffraction peaks for Pt appeared in XRD. And a good electrocatalysis for methanol oxidation was observed. The peak potential of the methanol oxidation appeared at ca. 0.63V(vs.SCE) and the peak current density for the oxidation was 78.1 mA cm~(-2) .

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Synthesis And Electrochemical Behavior Of Layered-Structure Limn_(1-X)Cr_Xo_2, Jie Xiao, Hui Zhan, Yun-Hong Zhou Aug 2004

Synthesis And Electrochemical Behavior Of Layered-Structure Limn_(1-X)Cr_Xo_2, Jie Xiao, Hui Zhan, Yun-Hong Zhou

Journal of Electrochemistry

The Layered-structure LiMn_(1-x)Cr_xO_(2 )(x=0,0.15) solid solution has been prepared by the rheological phase method. From the XRD results, undoped LiMnO_(2) crystallized almost entirely in the orthorhombic phase while the structure of LiMn_(0.85)Cr_(0.15)O_(2) belongs to monoclinic phase. TEM investigation shows that the final powder product consists of ultrafine spherical particles which are distributed homogeneously, with the average diameter ranging from 60 to 300nm. The initial discharge capacity of LiMn_(0.85)Cr_(0.15)O_(2) is much higher than that of undoped LiMnO_(2). After 40 cycles, the capacity retention for m-LiMn_(0.85)Cr_(0.15)O_(2 )is 94% at the current rate of 50mA/g under room temperature. The results of electrochemistry tests …

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Lithium Insertion Into Tio_2(B) Nanobelts Synthesized By The "Soft Chemical" Method, Cha-Geng Nie, Zheng-Liang Gong, Lan Sun, Juan Zuo, Yue-Kun Lai, Chang-Jian Lin Aug 2004

Lithium Insertion Into Tio_2(B) Nanobelts Synthesized By The "Soft Chemical" Method, Cha-Geng Nie, Zheng-Liang Gong, Lan Sun, Juan Zuo, Yue-Kun Lai, Chang-Jian Lin

Journal of Electrochemistry

TiO_(2)(B) Nanobelts were synthesized by using the "Soft chemical"method. The products were characterized by means of transmission electron microscope(TEM), X-ray diffraction(XRD), Raman spectrum and energy dispersive spectrum(EDS). Galvanostatic charging and discharging tests showed that lithium-ion intercalation/deintercalation occurred reversibly in the TiO_(2)(B) nanobelts electrode, and a high capacity (265 mAh·g~(-1)) can be obtained. The results suggested that TiO_(2)(B) Nanobelts might be a promising negative electrode material of second Lithium battery.

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Preliminary Study Of Speek Membranes For Direct Methanol Fuel Cells Application, Su-Zhen Ren Aug 2004

Preliminary Study Of Speek Membranes For Direct Methanol Fuel Cells Application, Su-Zhen Ren

Journal of Electrochemistry

This paper describes the methanol permeability characterization of SPEEK membranes and their feasibility for DMFC application. The SPEEK membranes showed a significant lower methanol permeation than Nafion~115 determined from voltammetric methods. An increase in open circuit voltage was found in the performance of SPEEK membranes in DMFC. The power density of the cell using SPEEK membrane was considerably poorer than that of Nafion~115. If modified properly, the SPEEK membranes can be chosen for DMFC application based on this study.

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Study On An Intermediate Temperature Planar Solid Oxide Fuel Cell, Shao-Rong Wang, Wen-Xia Chen, Ting-Lian Wen, Jia-Di Cao, Zhi-Yi Lv, Da-Qian Wang Aug 2004

Study On An Intermediate Temperature Planar Solid Oxide Fuel Cell, Shao-Rong Wang, Wen-Xia Chen, Ting-Lian Wen, Jia-Di Cao, Zhi-Yi Lv, Da-Qian Wang

Journal of Electrochemistry

Tape cast method was applied to prepare green sheets of Ni/YSZ anode supported YSZ thin film. After isostatic pressure treatment and cosintering, the YSZ film on the Ni/YSZ anode was gas-tight dense, and 15~30 μm thick. The area of the composite film was over 100 cm~(2). A Ce_(0.8)Sm_(0.2)O_(1.9 )(CSO) interlayer was sintered on to the YSZ electrolyte film to protect La_(0.6)Sr_(0.4)CoO_(3 )(LSCO) cathode from reaction with YSZ at high temperatures. The LSCO cathode layer was screen printed onto the CSO interlayer and sintered at 1 200 ℃ for 3h to form a single cell. The obtained single cell was operated …

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Fabrication Of Solid Oxide Fuel Cells And Analysis Of Their Structure And Performance, Nai-Tao Yang Aug 2004

Fabrication Of Solid Oxide Fuel Cells And Analysis Of Their Structure And Performance, Nai-Tao Yang

Journal of Electrochemistry

An intermediate temperature solid oxide fuel cell (IT-SOFC) was fabricated by co-copressing-sintering methods, and the electrolyte of Ce_(0.8)Gd_(0.2)O_(1.9) (CGO) and cathode materials of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-α) (LSCF) were prepared by sol-gel method. The effect of preparation methods on the microstructure of the prepared fuel cells was analyzed by SEM . It shows that the cells prepared by the co-pressing/co-sintering method possess a dense electrolyte layer and a compact interface between electrolyte and anode but a curved configuration, while those prepared by the colloidal technique have a flat configuration but the electrolyte layer is not dense enough. The maximum output power density of …

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Electrochemical Reduction Of Nitrobenzene On The Wc Electrode In Acidic Solution, Chun-An Ma Aug 2004

Electrochemical Reduction Of Nitrobenzene On The Wc Electrode In Acidic Solution, Chun-An Ma

Journal of Electrochemistry

The tungsten carbide (WC) electrode was constructed by using polyterafluoroethylene as binder. The electrochemical behavior of nitrobenzene on the WC electrode in acidic solution was investigated by cyclic voltammetry, linear scan method and chronoamperometry. Experimental results showed that WC electrode had good activity for the electrochemical reduction of nitrobenzene, and the electrode process was controlled by diffusion and electrochemical stepssimultaneously. The apparent active energy of the electrode process is 23.7kJ mol~(-1), while the active energy of the electrochemicalstep is 10.91kJ mol~(-1).

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Synthesis Of (S)-3-Phenylpropane-2-Tert-Butoxycarbonylamino- 1-Thiol And Its Electrochemical Behavior Self-Assembled On Gold, Sun Ru Aug 2004

Synthesis Of (S)-3-Phenylpropane-2-Tert-Butoxycarbonylamino- 1-Thiol And Its Electrochemical Behavior Self-Assembled On Gold, Sun Ru

Journal of Electrochemistry

The synthesis of (S)-3-Phenylpropane-2-tert-butoxycarbonylamino- 1-thiol(N-Boc-APT) from L-phenylalanine was reported. L-Phenylalanine was reduced to the corresponding amino alcohol, protection of the amino group using tert-butyl pyrocarbonate gave (S)-2-tert-butoxycarbonylamino-3-phenylpropane-1-ol, which was then O-mesylated and treated with potassium thioacetate in DMF to give 3-phenylpropane-2-tert- butoxycarbonylamino-1-etylmercapto. After the acetyl group was removed with ammonia in alcohol, the desired target molecular was obtained. The structure of intermediate and target molecular was conformed by IR and ~(1)HNMR. We made N-Boc-APT self-assemble-modificated gold electrode and investigated its electrochemical behavior. The CV results of methylene blue on nano-Au/N-Boc-APT SAM/Au electrode showed that nano-Au could speed this electron transfer …

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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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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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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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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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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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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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Effective Approach To Cyclic Steady State In The Catalytic Reverse-Flow Combustion Of Methane, Krzysztof Gosiewski Jan 2004

Effective Approach To Cyclic Steady State In The Catalytic Reverse-Flow Combustion Of Methane, Krzysztof Gosiewski

Krzysztof Gosiewski

Computer-based simulations of a reverse-flow reactor should be carried out till the attainment of the so-called cyclic steady state. Usuallythis state is achieved bythe method of direct dynamic simulations. In the paper of Unger et al. (Comput. Chem. Eng. 21 (1997) 5167.) special approaches, making use of various minimization algorithms based most often on Newton algorithms, are proposed. In the present paper one deals with a comparison and an appraisal of these methods, applied to the reverse-flow catalytic combustion of methane that occurs in coal-mine ventilation air.

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Air Quality Regulation Policy In Portugal, João F. Gomes Jan 2004

Air Quality Regulation Policy In Portugal, João F. Gomes

João F Gomes

Ten years after the publication of first air quality laws in Portugal, and seven years after the publication of the respective emission limits, it seems appropriate to analyse the degree of law enforcement by the Portuguese manufacturing industry. Therefore, based on the emission measurements made regularly by ISQ, as the only officially accredited laboratory, a set of about 400 sources is analysed in terms of the compliance with the emission limits regarding total suspended particulate, sulphur dioxide, nitrogen oxides and VOCs. The compliance is evaluated through a non-dimensional parameter and plotted versus the emission flow rate to derive conclusions: it …

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