Chemistry Commons^™

Oxygen Enrichment Effect Of Mno2-Pt/C Compound Catalyst To The Cathode Of Pemfc, Hong-Feng Xu, Mao-Feng Zhang, Quan-Quan Gan, Cai-Sheng Huang

Journal of Electrochemistry

TO study of the oxygen storage material of air cathode is crucial for increasing performance of proton exchange membrane fuel cell.Using the MnO₂ as oxygen storage materials,a MnO₂-Pt/C catalysts were prepared and is used to replace the conventional Pt/C in air cathode.The electrochemical performance of air cathode composed of MnO₂ supported on Pt/C and the properties of fuel cell composed of MnO₂-Pt/C were investigated by using the CV,galvanostatic dischange method and TEM.

Growth Mechanism And Morphology Of Electrodeposited Micro-Nanocrystalline Iron, Qiao-Xin Zhang, Jia-Ming Zhang, Li-Ning Yang

Journal of Electrochemistry

Effects of current density,reaction temperature,electrolyte concentration and surfactant on the electrochemical deposition of micro-nanocrystalline iron were studied.Morphologies and structures of the samples were characterized by SEM and XRD,the results showed that the electrodeposits is slice α-Fe under little current and the density,lower temperature and higher concentration,and the dentritic α-Fe is under opposite conditions,but the influence from surfactant is unconsicously.Moreover,the growth mechanism of the electrodeposits was also analysed here.

Studies On Catalytic Mechanism Of Li/Socl2 Batteries By Metal Phthalocyanine Complexes, Zhan-Wei Xu, Qing-Jin Sun, Bi-Yun Su, Tu-Lin Che, Yan-Hong Song, Yao-Min Li, Jian-She Zhao

Journal of Electrochemistry

Effects of metal phthalocyanine comlexes MPc(M= Mn(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ)) as electrochemical catalysts on the performance of Li/SOCl₂ batteries have been examined at constant resistance.And the reasons of MPc affecting the discharged voltage and discharged time of Li/SOCl₂ batteries were also brought forward.A few new viewpoints on the catalytic mechanism of the reduction of thionyl chloride by phthalocyanine complexes were proposed.

Electrochemical Capacitance Characteristics For Mno2/C Composite, Jun Gao, Xing-Kang Huang, Yong Yang

Journal of Electrochemistry

The MnO₂/C composite was synthesized by reduction of KMnO₄ with acetylene black.The products were characterized by XRD and SEM.We used MnO₂/C composite as the positive electrode material of the electrochemical capacitor.The performance of faradic psedocapacitance of the MnO₂/C electrode was studied in different electrolytes.The MnO₂/C electrode was tested by cyclic voltammetry,electrochemical impedance spectroscopy(EIS) and constant charge-discharge curves.The experimental results showed that the MnO₂/C composite has excellent performance.The specific capacitance of the MnO₂/C composite as 258 F/g is obtained at 5mA/cm² current density in 1mol/L KOH solution.It …

Electro-Chemical Oxidation Kinetics Of The V(Iv) In The Sulfuric Acid Solution, Yong-Lian Qiao, Qian Xu, Jie Zhang, Yu-Chun Zhai

Journal of Electrochemistry

The electro-chemical oxidation kinetics for V(IV) in the sulfuric acid solution were investigated by cyclic voltammetry and steady state polarization curves at a graphite,platinum or conducting polymer electrode.Some kinetics parameters for the electrochemical reaction of V(IV) were calculated according to the Tafel curves.The results showed that the exchange current density and reversibility of V(V)/V(IV) redox reaction at the graphite electrode is largest among the three electrodes.There is the broadest extent of water stability and large oxidgen evolution potential when the conducting polymer was used as a working electrode in the solution of VOSO₄(0.5 mol/L) and H₂SO …

Electro-Generated Mno2 In Supersonic Wave Bath And Its Application In Preparation Of Glyceraldehyde, Yan-Hong Cai, Li-Qun Chen, Ri-Yao Chen, Xi Zheng, Xiao Chen, Zhen Chen

Journal of Electrochemistry

Glyceraldehyde is prepared by using MnO₂/ Mn²⁺as the media in a cationic membrane electrolytic cell.Under ultrasonic high-frequency oscillation,the electro-generated nanometer MnO₂ dispersed in the solution with several tens nm till several micron.Then the MnO₂ is used for selective oxidation of glycerine to glyceraldehydes.The catalyzing selectivity of MnO₂/ Mn²⁺is high and the current efficiency may account to 97.4 %.

Electrocatalytic Separation For Dopamine And Ascorbic Acid Using Poly-Evans Blue Modified Glassy Carbon Electrode And Simultaneous Determination, Li-Qing Lin, Xin-Hua Lin, Hong Yao, Jing-Hua Chen, Guang-Wen Li

Journal of Electrochemistry

Voltammetric behavior of the Dopamine(DA) and ascorbic acid(AA) at Poly-Evans Blue modified electrode were studied and a novel method for determination of the content of DA and AA is established.In pH 4.5 phosphate buffer solution,the modified electrode shows enhanced sensitivity and excellent electrochemical discrimination to DA and AA.The relationship between oxidation peak current and the concentration of DA or AA is linear in the range of 1.0 10^-6 ～3.0×10^-5mol/L and 5.0×10^-6~1.05×10^-4 mol/L,the detection limit has been estimated as 2.5(10^-7 mol/L and 3.0 ×10^-7 mol/ L,respectively.The oxidable potential difference of DA and AA …

Prerapation And Supercapacitor Property Of Al Doped Co3O4, Xin Ge, Ye Chen, Chun-Xia Zhang, Chang Shu

Journal of Electrochemistry

With KOH as precipitator to prepare Aluminum doped Co₃O₄,X-ray diffraction indicated that the doping Al did not change the crystal structure of Co₃O₄.Electrochemical properties of the sample were tested by cyclic voltammetry and constant-current charge/discharge.The results showed that the chemical doping improved the specific capacitance.When the mol ratio of Co(Ⅱ) with Al(Ⅲ)was 1∶0.05,the specific capacitance was up to 518.07 F/g within 0～400 mV potenitial at current density 5 mA/cm².

Preparation Of Manganese/Chromium Hexacyanoferrate Modified Glassy Carbon Electrode And Its Electrochemical Behavior, Sheng-Tao Zhang, Xiao-Yan Han, Ming-Yue Xue

Journal of Electrochemistry

A film of poly(manganese/chromium hexacyanoferrate)(MnCrHCF)is formed on the glassy carbon electrode(GCE) by Cyclic Voltammetry scanning,and its electrochemical behavior was studied.Factors affecting the electro-deposition of the film such as pH values and sustaining electrolytes,were discussed.And mechanism of the reaction was investigated.

Study On The Nano Diamond Stable Water Disperse System And Applying In Composite Chromium Plating, Lai-Xiang Zhang, Hong-Bo Xie, Xue-Kui Ma, Guo-Wu Zhao, En-Cheng Yu, Jia-Zhi Wang

Journal of Electrochemistry

The nano diamond stable water disperse system was studied.The low-bublles sulfonic anion sufcace active agent had been choosed out for this system.The affect of different physics agitation mothed on the water separate system stablity were conpared.The nano diamond stable water separate system had been applied to the composite chromium electroplating on this tests.The depositing speed,hardnees and wearing capacity of plating layer were tested.And the metallography structure of plating layer was charasterized by SEM.The test results and reaction princeple were discussed.

Influence Of Chromium On The Semi-Conductive Property Of Passive Film Formed On Carbon Steel In Bicarbonate/Carbonate Buffer Solution, Jin-Bo Li, Jie-Wu Zhu, Mao-Sheng Zheng

Journal of Electrochemistry

The influence of chromium on the semi-conductive property of the passive film formed at carbon steel in bicarbonate/carbonate buffer solution,is investigated by using electrochemical impedance spectroscopy(EIS).The results showed that the passive film fomed at carbon steel appeared an n-type semi-conductive property,but if the passive film formed at carbon steel with 3% chromium content exhibited an a-p semi-conductive charatcer.The slopes of Mott-Schottky plot of two passive films increased with rising the formation potential,it indicating the defect density of the film decreasing,but for the passive film formed at carbon steel with chromium additive,its donor density was lower about one order of magnitude …

Fabrication And Charaterization Of Nitrogen-Doped Tio2 Nanotube Array And Its Visible Light Activity, Hui-Fang Zhuang, Yue-Kun Lai, Jing Li, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Nitrogen-doped TiO₂ nanotube array was fabricated by an electrochemical anodic oxidation followed a wet process.XPS result indicates that the nitrogen atoms were doped into lattice of TiO₂ nanotubes.The UV-Vis spectra show that the photoabsorption of N-doped TiO₂ nanotube array film is enhanced in the visible light region.Compared with the TiO₂ nanotube array film,the N-doped TiO₂ nanotubes exhibite a higher photocatalytic activity which is evaluated by the decomposition rate of methyl orange using the tungsten-halogen lamp as light source.

Inhibition Mechanism Of Imidazoline Derivate In Simulated Water From Deep Gaswell Containing Co2, Yuan Lu, He-Xia Liu, Jing-Mao Zhao

Journal of Electrochemistry

The electrochemical method and atomic force microscope(AFM) were applied to study the inhibition mechanism of Im-D,an imidazoline derivate inhibitor,for mild steel in CO₂ saturated solution.The imidazoline derivate can inhibit effectively CO₂ corrosion,make the steel surface smoother and belongs to the anodic controlled mixed-type inhibitor.Its adsorption on the surface of mild steel is a spontaneous and exothermic process accompanied by the decrease of entropy and follows the Langmuir adsorption isothermal equation.The lower temperature will facilitate the process.The changes in the apparent activation energy(Ea) and the pre-exponential factor(A) of the corrosion reaction before and after the addition of inhibitor were …

Preparation, Structure, And Cv Study Of The Supported Ptruir/Tic Electrocatalysts For Oxygen Electrodes, Sheng Sui, Li-Rong Ma

Journal of Electrochemistry

The PtRuIr/TiC electrocatalysts were prepared by method of reduction and deposition on TiC powders as supports together with ultrasonic wave dispersion.The sampls were characterized by BET surface area,scanning electron microscope,X-ray diffraction,and cyclic voltammetry techniques.The active components of Pt,Ru,and Ir particles(2.6%Pt,1.3%Ru,16%Ir,and 80%TiC,by mass) were mainly dispersed on the outer surface of the TiC supports,which structures were in favor of fine variable crystallites.It was found that the electrochemical performance of the PtRuIr/TiC electrodes was about three times as that of the unsupported electrocatalysts with the same active compositions for oxygen evolution reaction.After 120 times of CV cycles,there was almost no PtRuIr/TiC dissolving …

Investigation On The Electrochemical And Spectra Properties Of Myricetin, Dong-Mei Wu, Shuang Liu, Hong-Fu Gao, Jin-Lian Li, Hai-Yan Liu, Qi-Chao Liang

Journal of Electrochemistry

The electrochemical mechanism of redox and stability of myricetin were investigated using cyclic voltammetry and electronic absorption spectra.Two oxidation reactions and two reduction reactions were achieved in B-R buffer solution.The oxidation reactions were both due to oxidation of 4′-OH on ring B and 3-OH on ring C within a one electron one proton process.The reduction reactions both correspond to the transformation of 4-carbonyl group on ring C to intermediate radical,and intermediate radical to hydroxyl group within a one electron one proton process,respectively.The redox of myricetin is pH dependent because of deprotonation,resulting in an increase of the antioxidant ability upon formation …

Electrochemical Codeposition Of Ha/Collagen Coating And Preliminary In Vitro Tests, Yan-Li Xu, Long-Xiang Lin, Zhi-Wang Geng, Chang-Jian Lin

Journal of Electrochemistry

An electrochemical co-deposition technique has been developed to prepare a hydroxyapatite(HA)/collagen composite coating on Ti substrate.The SEM results show that the composite coating exhibits a homogeneous and porous morphology with nano-micro structure.And the XPS results demonstrate that the composite coating is formed by an organic-inorganic hybrization.In vitro cell culture tests reveal that,compared with pure HA and pure Ti,the HA/collagen composite coating exhibit a best biological properties.

Electrocatalytic Oxidation Of Methanol At The Nano Ni-B Amorphous Alloy Powdermicroelectrode, Yi-Xiong Zheng, Shi-Bing Yao, Shao-Min Zhou

Journal of Electrochemistry

Electrocatalytic oxidation of methanol at the nano Ni-B amorphous alloy powder-microelectrode in alkaline media was studied by using cyclic voltammetry.Compared to the highly preferred orientation(220) nickel electrode,The onset potential of methanol electrooxidation at the nano Ni-B microelectrode is negatively shifted about 0.04V,and the current density is increased approximately by 2 orders of magnitude.Thus,the nano Ni-B microelectrode has very strong electrocatalytic activity for the oxidation of methanol.The kinetic parameters were determined with the steady polarization curves.The results show that the rate constants for both the oxidation of Ni(Ⅱ) to Ni(Ⅲ) and the reduction of Ni(Ⅲ) to Ni(Ⅱ) at the nano Ni-B …

Pdms Regularly Superhydrophobic Surfaces Prepared By Icp Etching Silicon Model, Run-Xiang Zhang, Yu-Long Zhang, Hua-Shui Lin

Journal of Electrochemistry

A series of different dimensions regularly micropillar array hydrophobic Poly(dimethylsiloxane)(PDMS) surfaces were obtained by peeling off PDMS which was poured onto the silicon models.The silicon models were prepared by ICP etching technology.The results indicate that the water contact angle(WCA) was increased with the size and the height of the mocropillar,decreased with increasing the distance of the mocropillar when the height of the micropillar was relative small;if the height of the micropillar was relative big,WCA was decreased with increasing the size of micropillar,meanwhile,the distance of the micropillar was a complex factor to WCA,and the height of the micropillar have little influence.The …

The Syntheses And Electrochemical Performance Of Nano-Mno2 For Supercapacitor, Jun Ma, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Nano-manganese dioxide were prepared by two different methods which are low temperature solid reaction and chemical deposition.The products were characterized by XRD,SEM,BET and constant current charge-discharge tests.The result shows that there is a close relationship between specific capacitance and BET surface areas.Meanwhile the specific capacitance was impacted little by the structure of the nano-manganese dioxides.However,the product performance of high rates,was influenced by structure,the higher rate can be obtained with the more perfect crystal structure.

Morphology Of The Pb-Sn Alloy Thin-Layer Electrodeposition, Yan-Jun Du, Zhi-Gang Yin, Tong-Chi Xia

Journal of Electrochemistry

The morphology of Pb-Sn alloy thin-layer electrodeposition was studied.Experimental results showed that the morphology of deposit could vary as the concentration of Pb²⁺, Sn²⁺ two kind metallic ion to be changed.The patterns of product appeared the dendritic, ramification, dense branch, fractal, and homogeneous structure and their morphological evolution was caused by the change in anisotropy of crystal growth and different stage of electrodeposits.

Effect Of Tension On Corrosion Behavior Of Galvanized Steel Wire For Cable-Stayed Bridge, Xue-Ming Li, Jie-Min Zhou, Qiang Liu, Ling-Feng Kong, Jian-Ting Zhou

Journal of Electrochemistry

Corrosion of steel wire in cables is a major cause of cable-stayed bridge deterioration. The corrosion behavior of galvanized steel wire at different tension is investigated by polarization voltammetry method and neutral salt spray test in 5% NaCl solution. The physical and chemical properties of corrosion products are characterized by XRD and TG-DTA.The result shows that the corrosion current or corrosion rate of galvanized steel wire is larger with increasing the tension, the white rust of galvanized steel wires at different tension appears within one cycle, the red rust appears after 16 cycles at 15~22kN tension, and 23 cycles at …

Experimental Research On Electrostatic Atomization For Different Liquid Dielectrics, Zhao-Hui Wang, Zhen-Fang Liao, Quan-Jie Gao, Ying-Feng Hu

Journal of Electrochemistry

The equipment is self-designed and assembled for a high voltage electrostatic atomization experiment.Under the same environment,atomization process for the three different liquid dielectrics of kerosene,emulsifier and alcohol are studied in high voltage electrostatic field.It is shown that the effect of electrostatic atomization will be better as the surface tension and viscous force of liquid dielectrics is lower,whereas the conductivity is larger.Kerosene,emulsifier and alcohol can get the optimal atomization result at 40kV,10kV and 25kV respectively.

Synthesis, Characterization, And Cyclopolymerization Of A Functional Non-Symmetric Divinyl Monomer, Bekir Dizman, Lon J. Mathias

Faculty Publications

A non-symmetric divinyl monomer with terminal carboxylic acid functionality was readily synthesized from the reaction of ethyl α-hydroxymethylacrylate (EHMA) with maleic anhydride. The new monomer (EHMA–MA) was homopolymerized in both bulk and ethyl acetate using AIBN as an initiator to give cyclopolymers. The synthesis of the monomer and cyclopolymers were followed by ¹³C NMR, ¹H NMR, and FTIR. ¹H NMR was also utilized to obtain the degree of cyclization of the polymers, which were found to be 95% or higher in all cases. The molecular weights of the cyclopolymers were around 40–60,000 g/mol as estimated by SEC. …

The 14N Quadrupole Coupling In Hexamethylene Triperoxide Diamine (Hmtd), John Persons, Gerard S. Harbison

Gerard S. Harbison Publications

Using high-field NMR, we have determined the magnitude of the nuclear quadrupole interaction in hexamethylene triperoxide diamine (HMTD), the explosive allegedly used in the London bombings of July 2005. The experimental quadrupolar coupling constant, 5.334 MHz, is in good agreement with quantum chemical calculations. The predicted single zero-field transition frequency should lie in a relatively empty part of the 14N nuclear quadrupole resonance (NQR) spectrum; the spin relaxation rate is reasonably fast.

Fundamental Studies Of Hydrogen Storage And Catalysis, Balakrishnan Naduvalath

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …

Poly[Μ2-Nitrato-(Μ4-Pyrazine-2-Carboxylato)Disilver(I)], Kathryn L. Seward, Joseph M. Ellsworth, Zeeshan M. Khaliq, Hans-Conrad Zur Loye

Faculty Publications

The title compound, [Ag₂(C₅H₃N₂O₂)(NO₃)]_n, is a three-dimensional coordination polymer containing two-dimensional slabs held together by bridging nitrate groups. AgNO₄ and AgNO₅ silver coordination polyhedra arise. Weak argentophilic interactions [AgAg = 3.0686 (7) Å] occur in the crystal structure.

P–C And C–H Bond Cleavages Of Dppm In The Thermal Reaction Of [Ru3(Co)10(Μ-Dppm)] With Benzothiophene: X-Ray Structures Of [Ru6(Μ-Co)(Co)13{Μ4-Php(C6H4)Pph}(Μ6-C)] And [Ru4(Co)9(Μ3-Η2-Phpch2Pph2)(Μ4-Η6:Η1:Η1-C6H4)(Μ-H)], Shariff E. Kabir, Mohammad R. Hassan, Daniel T. Haworth, Sergey V. Lindeman, Tasneem Siddiquee, Dennis W. Bennett

Chemistry Faculty Research and Publications

The thermal reaction of [Ru₃(CO)₁₀(μ-dppm)] (1) with benzothiophene in refluxing toluene gives a complex mixture of products. These include the known compounds [Ru₂(CO)₆{μ-CH₂PPh(C₆H₄)PPh}] (2), [Ru₂(CO)₆{μ-C₆H₄PPh(CH₂)PPh}] (3), [Ru₃(CO)₉{μ₃-η³-(Ph)PCH₂P(Ph)C₆H₄}] (4) and [Ru₃(CO)₁₀{μ-η²-PPh(CH₂)(C₆H₄)PPh}] (6), as well as the new clusters [Ru₆(μ-CO)(CO) …

A Computational Chemistry Study Of Spin Traps., Jacob Fosso-Tande

Electronic Theses and Dissertations

Many defects in physiological processes are due to free radical damage: reactive oxygen species, nitric oxide, and hydroxyl radicals have been implicated in the parthenogenesis of cancer, diabetes mellitus, and rheumatoid arthritis. We herein characterize the phenyl-N-ter-butyl nitrone (PBN) type spin traps in conjunction with the most studied dimethyl-1-pyrroline-N-oxide (DMPO) type spin traps using the hydroxyl radical. In this study, theoretical calculations are carried out on the two main types of spin traps (DMPO and PBN) at the density functional theory level (DFT). The energies of the optimized structures, hyperfine calculations in gaseous and aqueous phases of the spin traps …

The Use Of Non-Natural Nucleotides To Probe Template-Independent Dna Synthesis, Anthony J. Berdis, David Mccutcheon

Chemistry Faculty Publications

The vast majority of DNA polymerases use the complementary templating strand of DNA to guide each nucleotide incorporation. There are instances, however, in which polymerases can efficiently incorporate nucleotides in the absence of templating information. This process, known as translesion DNA synthesis, can alter the proper genetic code of an organism. To further elucidate the mechanism of template-independent DNA synthesis, we monitored the incorporation of various nucleotides at the “blunt-end” of duplex DNA by the high-fidelity bacteriophage T4 DNA polymerase. Although natural nucleotides are not incorporated at the blunt-end, a limited subset of non-natural indolyl analogues containing extensive π-electron surface …

Hard/Soft-Acid/Base Principle And The Reaction Ahbs+Asbh → Ahbh+Asbs, Jerry Goodisman

Chemistry - All Scholarship

A demonstration of the hard/soft-acid/base principle involves showing that the energy change for Ah Bs + As Bh → Ah Bh + As Bs is always negative. We point out problems with assumptions made about hardness and strength of the components, but emphasize that problems with the way in which energies are calculated are even more important.