Chemistry Commons^™

Optimizing Catalyst Layer Composition Of Pemfc By Orthogonal Method, Ming-Hua Wang, Xin-Jian Zhu, Guang-Yi Cao, Sheng Sui, Qing-Chun Yu, Ming-Ruo Hu, Zheng-Yu Fan

Journal of Electrochemistry

The optimal composition of catalyst layer in a PEMFC electrode was studied through orthogonal method. It was showed that the performance of hydrophilic electrodes, in which there is no PTFE in the catalyst layer, were more favorable than that of hydrophobic electrodes. According to this condition, the power density of PEMFC attained 0.37 w·cm^-2 when the Nafion loading was 1.4 mg·cm^-2, and the Pt loading was 0.4 mg·cm^-2 in the catalyst layer, using H₂ as fuel and air as oxidant both at atmospheric pressure. Additionally, the results showed that increasing Pt loading in Pt/C catalyst …

Electronic Structures And Geometries Of Lial, Liang-Gen Wu, Rong-Qin Wu, Li-Juan Chen, Zi-Zhong Zhu, Yong Yang

Journal of Electrochemistry

LiAl is an important anode material for lithium batteries. Based on the plane-wave method and first-principles pseudopotentials, the electronic and geometric properties of LiAl have been studied. The cohesive energies versus volumes of unit cell, energy band structures, electronic density of states and charge density distributions of LiAl under some important structures are presented. The reason of B32-structure as the ground-state of LiAl crystal has also been elucidated, which is owing to Al-Al atoms in B32-structure form strong diamond-type covalent bonds. The present theoretical ground state structure of LiAl is consistent with the experimental and other theoretical results.

The Study On Carbon Nanotube-Loaded Pt Catalysts For Proton Exchange Membrane Fuel Cells, Hong Zhu, Feng-Juan Ge, Xiao-Hong Kang, Yu-Guo Yang, Yun-Hua Xu

Journal of Electrochemistry

Carbon nanotube-supported-platinum (Pt/CNTs) and carbon-supported-platinum (Pt/C) catalysts were synthesized by in-situ chemical reduction. They were analyzed using TEM and XRD, then made into electrodes to be part of assemable PEMFC for the performence tests. The resulted show that Pt clusters in both catalysts are of small particle size (about 4nm), and Pt/CNTs exhibits a higher catalytic activity than Pt/C.

Effect Of Dspp Al2O3 On Electrical Properties Of Polymer Electrolyte, Hai-Fen Xie, Xiao-Xiang Sun, Yi-Pin Wang, Guang-Yuan Li

Journal of Electrochemistry

The PEO-NaSCN polymer solid electrolytes by adding dispersed second phase particles (DSPP) of Al₂O₃ were studied. The characteristics of solid electrolytes and conductivity values are dependent on DSPP Al₂O₃ sizes and its contents. It was found that when the Al₂O₃ sizes are less than 1 μm, which is a criticle size, the sample conductivities were larger than those of the pure PEO-NaSCN samples and when the Al₂O₃ sizes are larger than 1 μm then the sample conductivities are less then those of the pure samples. The maximum conductivity …

Study On Degradation Of Phenol By Electrochemical Oxidation, Yue-Li Liu, Hong-Hua Ge

Journal of Electrochemistry

Electrochemical oxidation of phenol was carried out by the Dimensionally Stable Anodes (DSA) electrode, which has been discarded as waste by alkali chloride factory. The result indicates that a good phenol removal can be obtained under certain phenol concentration by the DSA electrode. The key factor in effecting phenol removal of electrochemical oxidation is applied current density, the following factors are pH, electrolyte concentration and phenol concentration. After experiments, the optimal test conditions are 30 mA/cm², pH 10, electrolyte concentration 10 mg/L, phenol concentration 10 mg/L.67% CODcr removal and 90% absorbance removal are gained by electrochemical oxidation for …

The Current Fluctuations Of Carbon Steel In Nano2-Nacl Solutions, Yu-Ming Tang, Yu Zuo

Journal of Electrochemistry

The characteristics of current fluctuations of A3 carbon steel in NaNO₂-NaCl solutions were studied with potentiostatic and potentiodynamic polarization methods. The steel remained stable passivation in 0.1 mol/L NaNO₂ solution without Cl^-. After NaCl was added in to the solution, current fluctuations with a characteristic of quick increase and slow decrease occurred, indicating quick dissolution and slow re-passivation of the metastable pits. The metastable pitting may cause accumulated corrosion damage around certain area and result in observable pits. With the increase of chloride concentration, the occurring potential for metastable pits Em rised, and peak values …

Determination Of Cystine By Second Order Differential Simple Oscillographic Voltammetry, Fu-Fang Tao, Jian-Bin Zheng

Journal of Electrochemistry

In 0.2 mol/L NaOH, cystine can cause an sensitive incision at -0.5 V (vs.SCE) of cathodic branch of dE/dt-E curve or second order differential simple oscillogram. Based on the oscillographic charateristic, second order differential simple oscillographic voltammetry was applied to the determination of cystine in tablet. The linear range and the detection limit for determination of cystine were 2.5×10^-6～3.5×10^-5 mol/L and 1.0×10^-6 mol/L, respectively. The relative standard deviation for 2.000×10^-5 mol/L cystine was 1.8% (n=5).

Adsorption And Oxidation Of Phenol Electrode Processes, Bao-Cheng Wang, Yan-Ping Sun, Jin-Hua Zhu

Journal of Electrochemistry

The electrochemical behaviors of platinum electrode were studied by cyclic voltammetry in 1mol/L sulfuric acid solution and 1mol/L sulfuric acid solution contained phenol. The adsorption characteristics of phenol and the intermediat on electrode surface have been discussed. The reactive reversibility and oxidation mechanism of phenol on electrode process have been investigated.The potential of characteristic adsorption was suggested. The various products woud be formed when the electrode potential was greater than the one of characteristic adsorption.

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix, Spencer M. Steinberg, David W. Emerson, Gary Cerefice

Separations Campaign (TRP)

The recovery of iodine released during the processing of used nuclear fuel poses a significant challenge to the transmutation of radioactive iodine. During the first year of this program we have examined the potential of Fullerene Containing Carbon compounds (FCC) developed by KRI, and natural organic matter (NOM) as sorbents for iodine released during the reprocessing of nuclear fuel. This work involved the development of bench-scale testing of the FCC and NOM material in a simulated process off-gas environment.

During the first two quarters of this program we explored various analytical methods available for measurement of iodine, iodide, and iodate. …

Photodissociation Of The Od Radical At 226 And 243 Nm, Dragana C. Radenovic, Andre J.A. Van Roij, Dmitri A. Chestakov, Andre T.J.B. Eppink, J J. Ter Meulen, David H. Parker, Mark P.J. Van Der Loo, Gerrit G. Groenenboom, Margaret E. Greenslade, Marsha I. Lester

Chemistry

The photodissociation dynamics of state selected OD radicals has been examined at 243 and 226 nm using velocity map imaging to probe the angle–speed distributions of theD(²S) and O(³P₂) products. Both experiment and complementary first principle calculations demonstrate that photodissociation occurs by promotion of OD from high vibrational levels of the ground X ²Π state to the repulsive 1 ²Σ⁻ state.

Synthesis And Electrochemical Properties Of K2Feo4, Ning Zhou, Shi-Hai Ye, Yong-Long Wang, Xue-Ping Gao, Dong-Feng Lin, Zuo-Xiang Zhou, De-Ying Song

Journal of Electrochemistry

The K₂FeO₄ used for new positive electrode materials was prepared. The primary batteries were used in different concentration of electrolyte and different currents. In 9 mol/L KOH , the capacity was the best. The higher the concentration of electrolyte, the lower the electric potential was. When the batteries discharged in 0.4 C , the capacity reached 521.3 mAh/g. By XRD, we gave the reasonable explanations for the discharge products of K₂FeO₄. Possible mechanism of discharge is discussed.

Synthesis Of Polyunit Vapor Phase Inhibitor And Its Volatile Corrosion Inhibition Performance, Da-Quan Zhang, Li-Xin Gao, Guo-Ding Zhou

Journal of Electrochemistry

A Mannich Base derivative (BMMCH), containing two morpholinum moieties and one cyclohexylamnonium moiety, was synthesized through aminomethy1 reaction. Its configuration was verified by IR and ¹H-NMR. Its volatile rustproofing effect was appraised by volatile rustproofing sieve test and vapor inhabitability test. The result shows that BMMCH has good protection effect for carbon steel. BMMCH has lower volatility compared with dicyclohexylamnonium nitrite (DICHAN) via closed space volatile weight-loss test. The inhibition mechanism was studied by potentiodynamic polarization electrochemistry technique in ASTM simulated atmospheric water. The corrosion potential of carbon steel electrode shifted to a negative direction when BMMCH was joined …

The Second Circular For 12th National Conference On Electrochemistry Of China, Chinese Society Of Electrochemistry (Cse)

Journal of Electrochemistry

No abstract provided.

Study On Adsorption Behavior Of Inhibitors On N80 Steel, Ai-Kui Li, Guo-Min Li, Xing-Peng Guo

Journal of Electrochemistry

The deadsorption behavior of four inhibitors on N80 steel with and without carbonate film was investigated by polarization and electrochemical impedance spectroscopy (EIS) techniques. It was found that, for different inhibitors, deadsorption behavior and adsorbability between with and without carbonate film are different. Furthermore, acidic inhibitor and small size molecule inhibitor shows different inhibition behavior.

The Technique Of Rare-Earth Conversion Coatings On Aluminum Alloy, Jun-Tao Wang, Jian-Hua Wu, Guang-Zhang Chen

Journal of Electrochemistry

The orthogonal design was used to screen the film_forming technique on LY12 aluminum alloy using quadrivalent cerium salt, and the corrosion-resistance performance of the coating was studied. The results revealed that: after LY12 aluminum alloy was treated by cerium salt, its pitting potential shifts to positive direction while the corrosion potential slightly decreases, showing that the alloy becomes less sensitive to pitting corrosion was greatly improved, comparable to that after chromate treatment; in addition, by combining the results of electrochemical measurements with surface analysis, the mechanism of corrosion-resistance on the race-earth conversion coating of the aluminum alloy was also discussed.

Study On The Electrochemical Behavior Of Methy1 Green And Methy1 Green-Cyclodextrin Supramolecule System, Yu-Jing Guo, Jing-Hao Pan, Chun-Hua Guo, Hong-Lian Zheng

Journal of Electrochemistry

Electrochemical behavior of methyl green in different kinds of solution and the supramolecule system of methyl green-cyclodextrin were studied. Inclusion constants of four cyclodextrin with emthyl green were determined by “electric current method”. The order of inclusion ability is HP-β-CD,β-CD,SBE-β-CD and CM-β-CD. The molar ratio of inclusion complexes of methyl green with CDs is 1:2. A possible mechanism was reported for methyl green.

An Electrochemical Prediction Method For Caustic Scc Of Fe-Cr-Ni Alloy, Chun-Bo Huang, Zhan-Peng Lv, Wu Yang

Journal of Electrochemistry

Stress corrosion cracking (SCC) of Fe-Cr-Ni alloy (alloy 800 M) in hot concentrated caustic solution was investigated by means of tests of C-rings under controlled potentials. The steady dissolution current densities (i_st) of the plate specimens and C-rings polarized potentiostatically were measured. The simplifed steady potentiostatical curves were drawn on the basis of i_st. The ratio R_PD measured from i_st and steady passive current density i p at low potentials (R_PD = i_st/i_p) was designed as a polarization dissolution susceptibility parameter. The parameter R_PD values of both plate …

Corrosion Fatigue And Dynamic Strain Aging Of Duplex Stainless Steel In Aqueous Solution, Chuan-Ming Tseng, I-Hsuang Lo, Wen-Ta Tsai

Journal of Electrochemistry

The corrosion fatigue and dynamic strain aging behaviors of 22%Cr duplex stainless steel (DSS) in sodium chloride solutions were investigated. Austenitic 316L SS and ferrtic 430 SS were also used in this study for a comparison. The experimental results showed that no stress corrosion cracking (SCC) occurred in all these SSs tested in 3.5wt% NaCl solution at 80 ℃. However, dynamic strain aging (DSA) occurred in 316L austenitic SS and 22%Cr DSS during slow strain rate testing (SSRT) in this solution.The occurrence of DSA was dependent on solution temperature,strain rate and the presence of austenitic phase. The corrosion rate of …

Comparison Of Thermal Cyclic Oxidation Of The Pvd Ni-Al And Hvof-Mcraly Coatings, J-T Chang, C-H Yeh, J-L He, K-C Chen

Journal of Electrochemistry

A PVD process-cathodic arc plasma ion plating was used to deposit Ni-Al films on Inconel 600 superalloy. The oxidation behaviors of PVD Ni-Al coating and the thermal sprayed CoCrAlY coatings were revealed and compared by performing cyclic thermal oxidation test at 1100 ℃ to evaluate its feasibility. Experimental results showed that the films with different compositions of Ni₆₂Al₃₈, Ni₆₃Al₃₇ and Ni₆₉Al₃₁ could be obtained when using Ni₅₂Al₄₈, Ni₆₀Al₄₀ and Ni₇₀Al₃₀ as targets, respectively. During the cyclic thermal oxidation test, the …

Fabrication Of Scanning Micro Cl- Probe And In Situ Imaging Of Cl- At The Interface Of 2024 Al Aloy/Solution, Yu-Hua Lin, Min-Hua Shao, Rong-Gang Hu, Yan Li, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Micro combination Ag/AgCl electrode with a tip measuring tens micron in diameter was fabricated. The probe satisfied in situ imaging of Cl^- distribution at metal surface in chloride solution because of its excellent linearity between potential and Cl- concentration, rapid response, good stability and selectivity. With the aid of the home made Micro Electrode Scanning system and scanning Cl^- probe, the effect of the [Cl^-] at 2024-Al/solution interface on localized corrosion process was investigated. It was demonstated directly that Cl^- ion in solution immigrated toward, then adsorbed preferentially and accumulated at the junction between the …

Effect Of Heat Laminating Aggregation Status Of Polymer Lithium-Ion Battery Cathode On Battery Performance, Ming-Gang Jin, Quan-Feng Dong, Ming-Sen Zheng, Li Huang, Hui-Qun Cai, Jin-Qua You, Zu-Geng Lin

Journal of Electrochemistry

Multi-layer heat laminated polymer lithium ion battery was made, the effect of temperature of cathode laminating on battry performance was also investigated. It was discovered that suitable temperature of cathode laminating is critical to battery performance and is a key parameter to manufacture process control of polymer lithium ion battery.

Electrochemistry And Electrocatalysis Of A Novel Μ-Oxamido Copper(Ⅱ) Binuclear Complex, Gui-Lian Gao, Guo-Bao Li, Qiu-Xia Yang, Xue-Lin Wang

Journal of Electrochemistry

In this paper, the cyclic voltammetric and spectroelectrochemical behaviors of μ-oxamido Copper(Ⅱ) Binuclear Complex (deCu) in PBS were studied. Cyclic voltammograms of this complex in PBS (pH=9) exhibited two reductive peaks (E_pc1 =-0.25 V, E_pc2 = -0.50 V) at hanging mercury drop electrode(HMDE), peaks at -0.50 V and -0.25 V corresponded to the reduction of ligand and copper(Ⅱ) complex, respectively. The spectroelectrochimical experiments showed that there was a new absorption band at 440 nm, and the absorption peaks at 270 nm, 280 nm red shifted to 300 nm, 310 nm under potential of -0.75 V. It was meant …

Influence Of Marine Organisms Upon Corrosion Of Steel Piling Systems, Jiunn-Shyong Luo, Cliff Rau, Kuei-Ching Chen

Journal of Electrochemistry

To study the influence of marine organisms upon corrosion of ASTM A36 steel piling sysems, specimens were immersed in both natural and synthetic seawater. Electrochemical techniques such as linear polarization resistance and electrochemical impedance scan(EIS) were applied to evaluate corrosion of the steel. The results indicated that attachment of marine organisms to form fouling layers on the steel surface reduced general corrosion, but localized corrosion occurred underneath marine organisms. An equivalent circuit model was established to simulate attachment of marine organisms upon carbon carbon steel surfaces.

Electrochemical Response Of Deformed Marine Steel In Sea-Mud Containing Sulfate Reducing Bacteria, Yan-Liang Huang

Journal of Electrochemistry

The corrosion failure behavior of marine steel is affected by stress,which exists in offshore structures at sea-mud region. In order to conduct the study of stress on the electrochemical response of a selected steel, a kind of natural sea-mud containing sulfate reducing bacteria (SRB) was collected. The electrochemical response of cyclic stress of the specimen with and without cracks in sea-mud was analyzed.

Severe Corrosivity And Its Eletrochemical Mechanism Of Seawater In Xiamen Sea Area To Al-Mg Alloys, Le-Yun Lin, Yue-Hong Zhao

Journal of Electrochemistry

The surface layer seawater of different sea areas in China exhibit different corrosivity to Al-Mg alloys according to the experiment results of 16 years exposure in seawater. The seawater in Xiamen sea area possesses severe corrosivity while seawater in Qingdao possesses the mildest corrosivity to Al-Mg alloys with better regularity of corrosion behavior. The present paper illustrates by experiment data that the strongest corrosivity of Xiamen seawater to Al-Mg alloys is owing to the low salinity of the seawater and the “electrolyte effect” come from it. The 16 year corrosion data and corrosion morphology of the typical Al-Mg alloys from …

Discussion On Factors Of Unstable 304 Stainless Steel Stress Corrosion Cracking, Xin-Sheng Zhang, Chun-Chun Xu, Gang Hu

Journal of Electrochemistry

The 304 stainless steels were stretched at low temperatures to get different martensite phase transformation. Ferrmagnetometer was used to measure the martensite phase content. It was found that the dislocation density of 304 stainless sted was increased unavoidably with increase of deformation. Transmission electron microscope (TEM) was used to study the distribution of the dislocation. The influence of microstructure change on SCC of 304 stainless steel was discussed by slow strain rate testing (SSRT) in 42% MgCl₂ boiling solution,metallurgical microscope and scanning electron microscope (SEM).The results showed that martensite phase and dislocation flaw act together on the SCC susceptibility …

The Electroless Plating Ni-Fe-P Alloy And Its Voltammetric Behavior, Sen-Lin Wang, Hui-Huang Wu

Journal of Electrochemistry

Electroless Ni-Fe-P alloy deposition from an alkaline bath, containing sodium hypophosphite as reducer, boric acid as buffer agent and sodium citrate as complexing agent, was investigated. To increase the plating rate and to inprove the bath stability, the deposition parameters were optimized. The effects of process parameters (pH, temperature and mole ratio of [Fe²⁺]/([Ni²⁺]+[Fe²⁺]) on the plating rate and deposit composition were examined and it was found that the presence of ferrous sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the percentage of iron in the electroless …

The Mechanism Of Electrocatalytic Reduction Of Oxygen On Manganese Dioxide, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai, Li-Fen Xiao

Journal of Electrochemistry

The oxygen electroreduction on the MnO₂ electrode was investigated by analysis of the polarzation properties of oxygen reduciton and its dependence on MnO₂ discharge state, in combination with the characterization of discharge intermediate and the kinetic parameters of the oxygen reduction. Based on the experimental observation and mechanistic analysis, it was suggested that the reduction of oxygen was closely related to the discharge behaviors of MnO₂. When MnO₂ was electrochimically reduced to MnOOH, it was immediately oxidized by oxygen molecules. Thus the oxygen reduction proceeds through continuous oxidation of the discharge product of MnO_{2 …}

Study Of Electrolyzed Pure Iron And Rrr-H Method, Wei-Min Cao, Ren-He Yin, Hui-Gen Yan, Yi-Bing Zhang, Ying-Chun Dai

Journal of Electrochemistry

The high purity electrolytic iron was made from scrap iron chips. The purity of electrolyzed pure iron was above 99.98% by chemical analysis. The resistivity was measured at 298 K and at 4.2 K under an applied longitudinal-magnetic field of 8000 e. The ratio of resistivity at 298 K to that at 4.2 K, The value of residual resistivity ratio (RRR H) roughly depended on the purity of iron. Pure iron electrolyzed on Ti substrate had very compact texture as evident by SEM.

Dramatic Nondipole Effects In Low-Energy Photoionization: Experimental And Theoretical Study Of Xe 5s, Oliver Hemmers, Renaud Guillemin, E. P. Kanter, B. Krassig, Dennis W. Lindle, S. H. Southworth, R. Wehlitz, J. Baker, A. C. Hudson, M. Lotrakul, D. Rolles, Wayne C. Stolte, I. Tran, A. Wolska, S. Yu, M. Ya Amusia, K. T. Cheng, L. V. Chernysheva, W. R. Johnson, S. T. Manson

Environmental Studies Faculty Publications

The Xe 5s nondipole photoelectron parameter γ is obtained experimentally and theoretically from threshold to ∼200  eV photon energy. Significant nondipole effects are seen even in the threshold region of this valence shell photoionization. In addition, contrary to previous understanding, clear evidence of interchannel coupling among quadrupole photoionization channels is found.