Physical Sciences and Mathematics Commons^™

Study On Modification Of Spinel Limn_2o_4 By Overcoating, Ren-Gang Zhang, Shi-Xi Zhao, Jung-Lei Xia, Han-Xing Liu

Journal of Electrochemistry

The surface of spinel LiMn 2O 4 was modified by the sol_gel process with LiCoO 2_coated LiMn 2O 4 and studied by XRD,SEM and EPMA.The results have shown that the surface of the coated grains heated at 700 ℃ for 10h,which is cubic spinel,were Co_rich.The amount of Co 3+ in the grains changed owing to different place of the grain and decreased from surface to inner parts. Using the coated as the cathode of Li_ion cells,the initial capacity deceased slightly,but the amount of Mn 2+ solving in electrolyte decreased,Jahn_Teller effect was suppressed to a certain extent.The LiCoO 2_coated LiMn 2O …

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 …

Modification Of Molybdenum Nitride Electrode For Supercapacitor(I)——The Effect Of Ammonium Vanadate On The Properties Of Molybdenum Nitride Electrode, Xue-Liang Li, Dao-Rong Luo, Hua-Lin Wang, Jian-Bo He, Yun-Guei Zhu

Journal of Electrochemistry

The effect of vanadium on the properties of the electrode of molybdenum nitride has been studied by using XRD?SEM and cyclic voltammetry.Modified molybdenum nitride was made as follow:films were coated by dipping titanium sheet in the solution containing different composition of molybdenum oxide,ammonium vanadate,ammonia,glycol and oxalic acid,and coated films are reacted with free ammonia.The results show that the specific capacitance of modified electrode was considerably increased and the operation voltage was broadened with the addition of ammonium vanadate in the dipping solution.The mechanism of these effects generated is the formation of new phase VOMoO 4 in the electrode of molybdenum …

Pure Hap Film Prepared By Direct Electrodepositing On Metallic Surface And Its Mechanism, Hao-Bing Hu, Chang-Jian Lin, Fei Chen, Ren Hu, Ming Guo

Journal of Electrochemistry

In controlling concentration of Ca 2+ and PO 4 3- in electrodeposition solution, the HAP film on Ti alloy has been deposited directly. Using XRD and SEM we have learned that prepared HAP is intact in crystal and equal in dimension. Thermodynamic calculation indicated that the HAP is easer formation of than that TCP of. With the XRD, SEM analyses and thermodynamic calculation, the electrodeposition mechanism has been discussed. It was proved that electrodepositon is a two_stage process and formation of HAP is a direct process from solution ions to HAP crystal without precursor.

Facilitated K~+ Ion Transfer By Db18c6 Across The Micro Liquid/Liquid Interface, Dong-Ping Zhan, Bing-Liang Wu

Journal of Electrochemistry

A novel microcavity Ag|AgCl electrode was fabricated to construct the micro_interface of two immiscible electrolyte solutions(ITIES). The transfer reactions of K + ion facilitated by DB18C6 across the water/1,2_DCE interface was investigated with the three_electrodes system. The corresponding reaction parameters were derived from the voltammetric data. The results showed that the microcavity electrode would be a useful and efficient tool to investigate the charge transfer reactions at ITIES.

Thionine-Glutathione Self-Assembly Monolayer Modified Electrdoe And The Quasi-Reversible Response Of Dopamine, Cheng Fang, Zheng Luan, Wu-Ming Zhang, Xing-Yao Zhou

Journal of Electrochemistry

Thionine was bound onto a glutathione monolayer self_assembled on the surface of a gold electrode previously, the electrochemical characteristics of which were studied. It was found that dopamine had a quasi_reversible response and cathodic characterstics peak could be used to determine the concentration of dopamine in the range of 1.0～300 μmol·L -1 in the presence of a higher concentration of ascorbic acid.

Corrosion Of Steel By Lead Bismuth Eutectic: Quarterly Report For May-June-July 2002, John Farley

Transmutation Sciences Materials (TRP)

The goal of this project is to understand the basic science of corrosion in the steel/LBE system.

We are taking more data, typically using the newly installed X-ray Photoelectron Spectrometry (XPS) apparatus, and analyzing our existing data. Undergraduate students Denise Parsons and Julia Manzerova have helped a great deal in the analysis of the data. We can obtain the elemental composition as a function of position within the sample. This gives clues to the migration of materials, the composition of the protective oxide layer, and the basic science of the corrosion process. We found dramatic differences between the exposed and …

Non-Dipolar Electron Angular Distributions From Fixed-In-Space Molecules, Renaud Guillemin, Oliver Hemmers, Dennis W. Lindle, E. Shigemasa, K. Le Guen, D. Ceolin, C. Miron, N. Leclercq, P. Morin, Marc Simon, P. W. Langhoff

Environmental Studies Faculty Publications

The first indication of nondipole effects in the azimuthal dependence of photoelectron angular distributions emitted from fixed-in-space molecules is demonstrated in N₂. Comparison of the results with angular distributions observed for randomly oriented molecules and theoretical derivations for the nondipole correction first order in photon momentum suggests that higher orders will be needed to describe distributions measured in the molecular frame.

Hydrogen-Induced Embrittlement Of Candidate Target Materials For Applications In Spallation-Neutron-Target Systems: Annual Progress Report (May 2001 – May 2002), Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate target materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including Alloy HT-9, Alloy EP 823 and Type 422 stainless steel. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these materials are being evaluated in environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. Further, the localized corrosion behavior of these alloys …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics: Quarterly Progress Report 03/16/02- 06/15/02, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The Lead-Bismuth eutectic (LBE) has been determined from previous experimental studies by the Russians and the European scientific community to be a potential material that can be used as a spallation target and coolant for the AAA proposed application. Properly controlling the oxygen content in LBE can drastically reduce the LBE corrosion to structural steels. However, existing knowledge of material corrosion performance was obtained from point-wise testing with very limited density. Scientists have noticed that the concentration of oxygen dissolved in the liquid alloy could control the corrosion rate of steels exposed to Pb or Pb-Bi. At high oxygen concentration, …

Modeling Corrosion In Oxygen Controlled Lbe Systems With Coupling Of Chemical Kinetics And Hydrodynamics-Phase Two, Samir Moujaes, Yitung Chen

Transmutation Sciences Materials (TRP)

The proposed work will combine chemical kinetics and hydrodynamics in target and test-loop lead-bismuth eutectic (LBE) systems to model system corrosion effects. This approach will result in a predicative tool that can be validated with corrosion test data, used to systematically design tests and interpret the results, and provide guidance for optimization in LBE system designs. The task includes two subtasks. The first subtask is to try to develop the necessary predictive tools to be able to predict the levels of oxygen and corrosion products close to the boundary layer through the use of Computational Fluid Dynamics (CFD) modeling. The …

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.

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 …

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 …

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.

The Electrochemical Etching Of Metals, Li-Min Jiang, Zhong-Qun Tian, Zhu-Fang Liu, Bin-Wei Mao, Hai-Gou Huang, Jian-Jun Sun

Journal of Electrochemistry

All kinds of current methods for etching metals are reviewed.The electrochemical etching methods among them,including through_mask,scanning electrochemical microscopy,confined etchant layer technique,electrochemical scanning tunneling microscopy and super_short potential pulse,are discussed in detail.The compositive analyses were made for the methods in terms of the processing precision(whether processing in micrometer or nanometer scale),the processing efficiency(the complexity of the procedure,and whether fabricating in batch),the extent of application(mainly refer to the procedure,and whether fabricating in batch),the extent of results was shown that each method has itself advantage and imperfection. The confined etchant layer technique has superiority over other methods in the view of the total …

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.

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 …

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.

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 …

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.

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 …

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.

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.

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 …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Aaa Task-4 Quarterly (December 1, 2001 – February 28, 2002) Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including HT- 9, EP 823 and 422. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these alloys will be evaluated in environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. The extent and morphology of cracking of these alloys will further be evaluated …

Third Quarter Report, Covering January Through March 2002, John Farley

Transmutation Sciences Materials (TRP)

Progress from June 2001-November 2001 was presented at the winter meeting of the American Nuclear Society in Reno (November 12-15, 2001), and incorporated into a refereed conference proceeding. A copy of the refereed conference proceeding has been provided to Tony Hechanova. In brief, the paper described the new program to examine the corrosive effects of lead-bismuth eutectic (LBE) on steels. We employed various types of surface studies (Scanning Electron Microscope [SEM], and X-ray Photoelectron Spectrometry [XPS]) to examine steel samples that had been exposed to LBE for various lengths of time at various temperatures. The goal is to understand the …

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 …

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.