Physical Sciences and Mathematics Commons^™

Optimum Of Catalyst Layers For Direct Methanol Fuel Cells, Jun Zhang, Lei Li, Li Xu, Yu-Xin Wan

Journal of Electrochemistry

The performances of membrane electrode assemblies (MEAs)with various Pt loading were compared.The amount of Nafion in a catalytic layer was optimized,and the effect of Nafion loading on the resistance of MEAs was investigated with ac impedance spectroscopy.For a MEA with both Pt 4 mg/cm 2 in the anode and the cathode,suitable Nafion loading was 21.4 wt% in the anode.With 21.4 wt% Nafion loading in the cathode,the Direct Methanol Fuel Cells(DMFC) showed the highest performance at high current density.While,the DMFC performances came down,as Nafion loading increasing,for ohm and concentration polarization.

Electrochemical Degradation Of Organic Wastewater By Three-Dimensional Electrode Reactor, Chun He, Tai-Cheng An, Ya Xiong, Dong Shu, Hui-Ling Hu, Xi-Hai Zhu

Journal of Electrochemistry

The electrochemical degradation of aniline was investigated using a novel electrochemical reactor, three_dimensional electrode reactor. The experimental results indicated that the reactor could efficiently remove aniline. The removal efficiency could be attributed to a combination of direct and indirect electrochemical reactions,that is,anodic oxidation and oxidation of electrogenerated H 2O 2 and hydroxyl radicals generated in electro_Fenton process. It was also observed that the removal efficiency was significantly dependent on applied voltage,Fe 2+ concentration,pH value and electrolysis time. In the experimental range they all have a positive effect on the removal efficiency except for pH value. Furthermore,hydroxyl radicals generated in electro_Fenton …

44th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 44th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Denver, Colorado, July 28 - August 1, 2002.

Effect Of Cl - On The Transition Current Density Of Zn During The Electrodeposition Of Zn-Ni Alloys, Ren-He Yin, Zheng-Hua Fang, Wei-Min Cao

Journal of Electrochemistry

There exists a transition current density of Zn when the normal co_deposition of Zn_Ni alloys at chloride baths turns to anomalous type.The value increases with Cl - concentration, but is independent of pH, this is because the existence of Cl - decreases the evolution overpotential of Ni metal and has a catalytic effect on it.

Recent Developments In The Electrolyte For Lic _6/Electrolyte/Cathode Battery, Cui-Ying Wang, Sheng-Liang Zhao, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

We present a reviewed the development and status of electrolyte for LiC 6/electrolyte/cathode battery. The effect of the salt, solvent, additive and impurity on the conductivity of the electrolyte, formation of the solid_electrolyte_interphase (SEI) and cycle life of the battery were described.

Electrosynthesis Of Glyoxylic Acid In A Cooled Cathode Reactor, Jin-Hong Fan, Jun Li, Xue-Yun Chen, Wei Li, Hao-Qi Gao

Journal of Electrochemistry

Glyoxylic acid was produced by electroreduction of oxalic acid in a well designed cooled cathode reactor. The cathodic and anodic electrolytes were super_saturated oxalic acid and hydrochloric acid aqueous solutions separated by a super_acid ion_exchange membrane. The current efficiency and time_space yield of glyoxylic acid were studied under different temperatures of cathode and electrolyte,current densities,materials of cathode. With the cooled cathode reactor, the energy consumption was reduced and higher oxalic acid concentration was available in solution, so that current efficiency was improved. The results indicated that the average time_space yield of glyoxylic acid was about 0.032 kg·dm -3 ·h -1 …

An Investigation On Sr-Doped Spinel Phase-Lisr Xmn _(2-X ) O _4, Hui Zhan, Yun-Hong Zhou

Journal of Electrochemistry

Sr_doped spinel phase_LiSrxMn 2-x O4 was successfully prepared by solid_state method. Structural and electrochemical characterizations were carried out. Although Sr 2+ has a large ion radius_1.12 ,the spinel structure can be well maintained for LiSrxMn 2-x O4 sample as far as the x value doesn't surpass 0.05. Electrochemical study presents supporting evidence that doping the stoichiometric LiSrxMn 2-x O4 phase with Sr is an effective way to improve the cycleability of LiSrxMn 2-x O4 spinel material. A remarkable enhancement of the cycleability with retention of the initial capacity >90 % after 95 cycles was observed for the Sr_doped spinel.

A Blend Conducting Membranes For Direct Methanol Fuel Cells, Lei Li, Jun Zhang, Hong Wu, Yu-Xin Wang

Journal of Electrochemistry

An attempt was made to modify membranes for direct methanol fuel cells by blending Nafion or polystyrene sulfonic acid (PSSA) with polyvinylidene fluoride (PVDF) from their solutions. The proton conductivity and methanol barrier property as a function of the membrane compositions are discussed. Compared with the Nafion  117 membrane, the PVDF_Nafion blend membranes with 25 wt% of Nafion showed a decrease in the conductivity by about 2 orders of magnitude, and the methanol barrier properties increased about 3 orders of magnitude. If the ratio (σ/P) is adopted to characterize the performance of the membrane, the PVDF_PSSA and PVDF_Nafiion blend …

Corrosive Electrochemical Behavior Of Carbon Steel In Microbiological Medium, Jing Liu, Hong-Bo Fan, Hai-Ping Xu, Jia-Shen Zheng, Li-Ming Xu, Zong-Qiang Mao

Journal of Electrochemistry

Sulfate_reducing bacteria(SRB)grows and propagates, PH of the solution is dropped from 7.5 to 5.8,and forms the biofilms on carbon steel in culture medium.The micro_environment on the surface of carbon steel is changed under the biofilms,the factors accelerate the formation of the pitting corrosion. When the biofilm on carbon steel is cleaned out,the surface of carbon steel have the non_uniform pitting corrosion. The activity of SRB and the porous structure of biofilms induced the initiation and development of the pitting corrosion of carbon steel.The process of microbiologically induced corrosion(MIC) involves the development of SRB activity,which promotes the permeation of gydrogen into …

Preparation,Structure And Properties Of Electrochromic Rhodium Oxide Films, Hai-Hong Wang, Tao Wang, Man-Ming Yan, Zhi-Yu Jiang

Journal of Electrochemistry

Electrochromic rhodium oxide films were prepared on ITO substrate by sol_gel method. The films exhibited reversible two_color (bright yellow at reduction and dark green at oxidation) electrochromic behavior in alkaline solution with good cycle stability. In_situ XRD, TGA_DTA, IR, XPS methods were used for studying the structure and chemical process of the films. The diffusion coefficient during the electrochromic process was measured by electrochemical impedance spectra method. It was found that the rhodium oxide films may be suitable for the use in electrochromic devices.

Studies On Sulfate Reducing Bacteria Influenced Corrosion Of 90/10 Cu/Ni Alloy, Guang-Zhou Liu, Jian-Hua Qian, Yan Ma, Jian-Hua Wu

Journal of Electrochemistry

Electrochemical techniques such as measurements of corrosion potential,the polarization resistance,and potentiodynamic scanning technique were used to investigate the electrochemical behavior of 90/10 Cu/Ni alloy in Postgate C medium containing sulfate reducing bacteria(SRB).The results showed that the corrosion potential of the alloy changed from -0.20 to -0.75 V(SCE) when bacteria inocula was added, and the polarization resistance R p decreased obviously,which corresponds to an increased corrosion rate. The shape ofthe anodic polarization curves was drastically changed in the presence of SRB, and an active_passive transition was observed. Electron probe microanalyzer was used to investigate the morphology and chemical composition of the …

The Preparation And Characterization Of Growing Preferentially Cds Nanopartile Film, Huai-Guo Huang, Yan-Yan Xi, Zhi-Xin Zheng, Jia-Wei Yan, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

CdS nanoparticle films were prepared on the PANI film,PATP film,Au film and ITO respectively by constant current deposition or current impulse method,and their structure and character were also studied.The results show that the substrates influence the structure and character of CdS particle film.

Polishing Rate And Dependent Factors Of Copper In Nh_3·H _2o Aqueous Solution Containing K _3fe(Cn)_6 During Cmp, Han-Wei He, Yue-Hua Hu, Ke-Long Huang

Journal of Electrochemistry

Dependence of polishing rates of copper on concentrations of NH 3·H 2O, passivator K 3,γ_Al 2O 3 abrasives and polishing pressures, polishing rotative rates were studied. Dependent mechanisms were explained. It was shown a linear relation between polishing and polishing pressures and rotative rates within some range, non_linear relation between polishing and various reagent concentrations. Preston coefficient was varied. CMP recipe of the best polishing rate was gained: 4%K 3Fe(CN) 6+1%NH 3·H 2O+25%γ-Al 2O 3, K p=0.023 83. Technics conditions were 300 rpm and 80 kpa. The best polishing effect was R a=50 nm, R max =400 nm.

Self-Assembled Monolayer Of Schiff Bases On Au Electrode, Ke-Qiang Ding, Qing-Fei Wang, Zhen-Bin Jia, Na Tian, Ning Wang, Ru-Ting Tong, Xin-Kui Wang, Hui-Bo Shao

Journal of Electrochemistry

Schiff bases tailored with _SH group,was self_assembled on Au substrate for the first time.The packing degree of this monolayer was described with SEM technique.Spontaneously,the self_assembled monolayer (SAM) was briefly characterized with CV and EIS methods.Though Comparing with the SAM of alkanethiol,the membrane we fabricated was relatively loose,our work is the first step to study Schiff bases by means of self_assembled monolayer.

Syntheses And Photoluminescence Of Zinc Oxide Polyaniline Coaxial Nanowires And Their Array, Zhi-Xin Zheng, Yan-Yan Xi, Ping Dong, Huai-Guo Huang, Jian-Zhang Zhou, Lin-Lin Wu, Zhong-Hua Lin

Journal of Electrochemistry

A novel nanomaterial,zinc oxide (ZnO) and polyaniline (PANI) coaxial nanowires and their array in the template,was synthesized using anodic aluminum oxide (AAO) membrane as template.The morphology of these coaxial nanowires was observed with transmission electron microscope (TEM).The experiments on photoluminescence (PL) of coaxial nanowires and their array in AAO membrane show that the visible emission band of ZnO shifts from 530 nm to 400 nm and the luminescence is enhanced for the coaxial nanowires array in AAO membrane,and the visible emission band shifts to a lower wavelergth(385 nm) for coatial nanowires in NaOH solution. Possible explanations for these two blue …

Electrochemical Properties Of Mixed Metal Oxide Coated Titanium Anodes In Seawater, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen

Journal of Electrochemistry

Mixed metal oxide coated titanium anodes prepared by thermal decomposition were characterized by scanning electron microscopy and electrochemical measurement, while the consumption rate of an anode was also measured in seawater. In order to examine the practical performances of mixed metal oxide_coated anodes, a simulating test on floating dock in seawater has also been carried out. The SEM results indicate that oxide layers exhibited a cracked_mud morphology which endows the anode with good electrocatalytic activity. The electrochemical measurements showed that mixed metal oxide_coated anodes exhibit excellent electrochemical activity and electrochemical stability in seawater. Owing to good corrosion resistance and low …

Development Of 200～500 W Portable Proton Exchange Membrane Fuel Cell Power System, Li-Qing Hu, Li-Rong Zhou, Zheng Li, Jian-Wei Xia, Ming-Zhu Fu, Xin Wu, Yun Zhu

Journal of Electrochemistry

The Properties of the Portable PEM Fuel Cell Power Source are very unique compared with the common primary or rechargeable electro_chemical battery. This paper describes the In this work, of the 200～500 W portable PEM fuel cell power system, was developed. The system mainly composed of four subsystem:1)Fuel cell stack;2)Air delivery;3)Hydrogen source;4)Heat dissipation and system control.

Electrocatalytic Oxidation Of Formaldehyde On The Proline Film Modified Electrode, Yu-Rong Ma, Qiu-Xia Yang, Guo-Bao Li, Zheng-Kai Xi, Xue-Lin Wang

Journal of Electrochemistry

The proline film modified electrode and its electrochemical behavior was studied by cyclic voltammetry and spectroelectrochemistry . After incorporation of Ni(Ⅱ), the cyclic voltammograms of the proline Ni(Ⅱ) film electrode exhibited a typical redox peak, which appeared at potential of 0.52 V anodic and 0.44 V cathodic in NaOH. The formal potentials E ' were linearly dependent on the pH, and the peak currents ip were linearly dependent on the square root of the scan rates,thus charge transfer in the film was controlled by diffusion. The diffusion coefficient is figured out to be 2×10 -10 cm 2·s -1 . The …

Scitech News Volume 70, No. 3 (2016)

Sci-Tech News

Table of Contents:

Columns and Reports

From the Editor 3

Division News

Science-Technology Division 4

Chemistry Division 6

Conference Reflections (SPARKS Award Recipient) 12

Engineering Division 14

Engineering Division Awards Report 23

Aerospace Section of the Engineering Division 25

Reviews

Sci-Tech Book News Reviews 26

Adverstisements

IEEE 24

WeBuyBooks.net 28

Photocurrent Enhancement By Ticl_4 Post_Treatment For Tio_2 Nanoporous Film Electrode, Yan-Jie Ren, Li Zhang, Sheng-Min Cai

Journal of Electrochemistry

Enhanced photocurrent in dye_sensitized photoelectrochemical cell was obtained by post_treating the TiO 2 nanoporous film electrode with TiCl 4. By investigating the effect of the post_treatment on surface area, pore size distribution, laser pulse induced current transient of the film electrode, photocurrent increase by the post_treatment was assigned to the improved electron percolation resulting from broadening of interparticle neck.

An Investigation Of Inhibition Mechanism Of Cerium For Aluminum Alloy 2024-T3, Min Hua Shao, Yan Fu, Rong Gang Hu, Chang-Jian Lin

Journal of Electrochemistry

Cerium compounds are promising inhibitors for aluminum alloy. However, the inhibition mechanism is not very clear. Scanning microreference electrode(SMRE)technique was used to probe the potential imaging of Al 2024 T3 in NaCl and CeCl 3 solution. The results of SMRE showed that in NaCl solution a severe localized corrosion occurred on the surface of Al 2024 specimen at once and maintained for a long time. The corrosion activity of Al alloy in CeCl 3 decreased with immersion time and disappeared finally. Additionally, the competition of inhibition and aggression between Ce 3+ and Cl - on Al alloy was in situ …

Electrosynthesis Of Glyoxylic Acid In A Packed Bed Reactor, Jin-Hong Fan, Jun Li, Yu-Zhong Su, Hao-Qi Gao

Journal of Electrochemistry

Glyoxylic acid was produced by electroreduction of oxalic acid in a packed bed reator.The cathodic and anodic electrolytes were super_saturated oxalic and hydrochloric acid aqueous solutions separated by a super_acid ion_exchange membrane.The current efficiency and yield of glyoxylic acid were studied under different structured packed bed reactors and different electrode materials,temperatures and current densities.The results indicated that the current efficiency of synthsis of glyoxylic acid was over 66.2% and the concentration of glyoxylic acid could reach 2.02% after 45min electrolysis with cathode of lead particles and anode of graphite board under conditions of temperature 32 ℃,superficial flow rate of 0.505 …

Photoelectrochemistry Of La~(3+) Doped Semiconductor Porous Films Sensitized By Ru(Bpy)_2(Ncs)_2 Dye, Li Zhang, Yan-Jie Ren, Sheng-Min Cai

Journal of Electrochemistry

The La 3+ _doped TiO 2 nanoparticles were prepared with hydrothermal method.The photoelectrochemical properties of La 3+ _doped TiO 2 nanoporous_film electrode sensitized by Ru(bpy) 2(NCS) 2 were studied.The conversion efficiency of light to electricity and the energy conversion efficiencies were ineased with the depth of La 3+ _doped TiO 2 nanoporous_film electrode.

Raman Spectroscopic Study On Mechanism Of Aluminum Triphosphate Pigment, Zhi-Jun Gu, Yong-Gui Liao, Zhi-Gang Zhang, Qi-Long Guo, Fang-Teng Su

Journal of Electrochemistry

The painted steel sample whose coating contained anticorrosive pigment has been investigated by Raman spectroscopy.The protective mechanism of aluminum triphosphate pigment for A3 steel is proposed as follows: Aluminum triphosphate can be dissolved and arrive at the surface of the steel.The dissolved triphosphate ions can complex with ferric ions.And the new products,namely ferric triphosphate,can strongly adhere at the surface of the steel by chemical bonds slowly.At last,a compact protective film,which effectively separates the steel substrate from the aggressive media,is formed at the steel surface.

Uncertainty In Determination Of Hydrogen Diffusion Coefficient In Metal Hydride Electrode Based On The Transition Region Of Diffusion-Controlled Impedance, Xian-Xia Yuan, Nai-Xin Xu

Journal of Electrochemistry

Hydrogen diffusion coefficient in MlNi 3.75 Co 0.65 Mn 0.4 Al 0.2 metal hydride electrode has been determined with transition region of diffusion_controlled impedance.Multiple solutions were obtained at each data point because of the periodic characteristic of some functions used in the calculation,and the maximum difference between the solutions reached several orders of magnitude.On the other hand,the solutions varied for different data points in the transition region of diffusion_controlled impedance of the same experimental plot.It could be concluded that this method is not so well defined and some modification is required.

Varying Current Electro-Synthesis Of Glyoxalic Acid In Pairs In The Fixed-Bed Electrolytic Cell, Yin Sheng Chen, Xin Sheng Zhang, Ying Chun Dai, Wei Kang Yuan

Journal of Electrochemistry

As for the process of the electro oxidation of glyoxal to glyoxalic acid, the electrolytic result of either fixed bed electrolytic cell or varying current electrolysis was better than that of either flat plate electrolytic cell or constant current electrolysis. The average current density of varying current electro synthesis of glyoxalic acid in pairs was 1535 A/m 2 and the current efficiency were 85.3% and 86.7% and the selectivity were 93.9% and 94.0% for the anodic oxidation and cathodal reduction respectively. The initial composition of anodic electrolyte was 7% glyoxal and 8% hydrochloric acid (W/W) and the cathodal electrolyte consisted …

Electrochemical Synthesis And Characterization Of The Nickel Electropolyurushiol Coordination Polymer, Feng Gao, Guo-Cai Shen, Jie-Yuan Tang, Wen-Gong Zhang

Journal of Electrochemistry

The nickel electropolyurushiol coordination polymer(EPU Ni 2+ ) was obtained by the reaction between nickel chloride isopropyl alcohol solution with electropolyurushiol (EPU).The electrochemical polymerization of urushiol and the preparation of nickel electropolyurushiol coordination polymer were investigated.The coordination polymer was characterized by XPS,FT_IR,DMTA and AES methods,and its composition and structure were determined.The content of Ni 2+ reached up to 7.5%. It was shown that there was certain coordination between Ni 2+ and electropolyurushiol in the coordination polymer,thus cross_links were formed.Therefore the glass transition temperature of the coordination polymer increased and heat resistance was enhanced considerably.

Effect Of The Brightener On The Behavior Of The Silver Electrodeposition, Jin Hu, Hui-Min Wu, Xiang-Ming Feng, Wei-Dong Li, Zheng-Zhong Zuo, Yun-Hong Zhou

Journal of Electrochemistry

The effect of the brightener on the behavior of the silver electrodeposition in cyanide solution was studied by potentiostatically step and rotating dise electrode(RDE) as well as X_ray diffraction (XRD) and scanning electron microscope (SEM).It was found that the silver electrodeposition was not changed by the addition of the brightener to the fundarmental solution.But it apparently increased the solution's micro_leveling effection and remarkably improved the coating's surface lightness.The coating's orientation isn't changed by the addition of the brightener in the light of the XRD result.The effectivness of the brightener was also discussed by the half_wideth of the XRD.

Further Evidence For Surface Properties Of Porous Silicon Resulting In Electroluminescence, Zhan-Jun Zhang, Bin Wu, Jing-Jian Li, Zhong-Fan Liu, Sheng-Min Cai

Journal of Electrochemistry

The electroluminescence of porous silicon in solutions at positive biases was investigated by luminescence spectrometer. The electroluminescence of porous silicon in solutions mainly depended on its surface properties. The elelctroluminescence was much enhanced when the sample of porous silicon was electrolyzed once again which had undergone an electroluminescence test. The tests of both cyclic voltammetry and the luminescence of the sample of porous silicon prepared by repeated electrolysis provided further evidence that the electroluminescence of porous silicon in solutions at positive biases stemmed from the oxidation of Si_H on the surface of porous silicon. The voltage tunable emitting for porous …

Determination Of Copper In The Waste Water Of Plating By Chronocoulometry For Flowing Solution, Xin-Hua Lin, Wei Chen

Journal of Electrochemistry

The chronocoulometry for flowing solution was devoloped and applied to the detemination of copper(Ⅱ) in the waste water of plating.The linear range of copper(Ⅱ) was 2～16mg/L,and the relative standard deviation was less than 0.1% ( n =8).The recovery was 98%～103% for copper(Ⅱ) in the waste water.Chronocoulometry for flowing solution overcomed noise disturbance resulting from capacity current and variety of property of electrode surface.This method was sensitive,accurate and well reproducible.