Chemistry Commons^™

Studies Of Infrared Optical Properties Of Palladium Nanoparticles With Different Sizes And Dispersed States, Yan-Xia Jiang, Hong-Gang Liao, Wei Chen, Shi-Gang Sun

Journal of Electrochemistry

Pd nanoparticles with different sizes and dispersed states were prepared. Their infrared optical properties were studied with CO molecule probe. The infrared spectroscopic investigation revealed that Pd_n of 6.6 nm and Pd_n(cube)of 100～150nmexhibit normal IR absorption. The center of IR bands are around 1970 cm^-1 and 1910cm^-1. Pd_nis introduced into the surface of electrode, and is induced by interface electric fieldto form the aggregation of nanoparticles Pd_n(ag). The Pd_n(ag) has a different IR optical property from Pd_n. The direction of IR absorption band of Pd_{n …}

Electrocatalytic And Lifetime Studies Of Commercial Catalystsin A Pemfc, Cheng Xuan, Yan-Yun Ma, Li Qi, Cheng Peng, Ling Chen, Jun Zhao, Ying Zhang, Qin-Bai Fan

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 …

Preparation And Optical Properties Of Highly Ordered Cds Nanowire Arrays, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Highly ordered CdS nanowire arrays have been prepared by using dc electrodeposition in the porous anodic aluminum oxide template. Scanning electro microscopy (SEM) and transmission electron microscopy (TEM) reveal that the nanowires are uniform and highly ordered. The measurements of X-ray diffraction and high-resolved electron microscopy (HRTEM) show that the nanowires are hexagonal structure with the crystallographic c-axis preferentially oriented along the length of the pore. The UV-Vis absorption spectra of CdS nanowire arrays show that the absorption edges of the nanowire arrays shift towards short wavelength with the decrease of the nanowire size. The photoluminescence measurements show that the …

Direct Electron Transfer Of Redox Proteins And Enzymes Promoted By Carbon Nanotube, Chen-Xin Cai, Jing Chen

Journal of Electrochemistry

The redox proteins (enzymes), such as hemoglobin (Hb), horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on the surface of the carbon nanotube modified with glassy carbon (CNT/GC) electrode, respectively. The experimental results showed that the redox proteins (enzymes) underwent effective and stable direct electron transfer reaction at the surface of CNT/GC electrode with a pair of nearly symmetrical redox peaks in phosphate buffer solution. The formal redox potential, E^0' , is almost independent on the scan rates, the average value of E^0'  for Hb, HRP and GOx is -0.343±0.001, -0.319±0.002 and -0.456±0.001 V (vs.SCE,pH 6.9), respectively. …

Stability And Electrochemical Performance Of Nio Cathode Modified By Zno Additive For Mcfc In Molten Carbonates, Bo Huang, Fei Li, Qing-Chun Yu, Gang Chen, Ke-Ao Hu

Journal of Electrochemistry

The ZnO/Ni composite cathode was fabricated by tape-casting method, which microstructures and phases were studied. The electrochemical behaviors of ZnO impregnated NiO cathodes were also evaluated in molten 62 mol%Li₂CO₃ + 38 mol%K₂CO₃eutectic at 650 ℃ by electrochemical impedance spectroscopy (EIS) as a function of ZnO content and immersion time. The ZnO impregnated nickel cathodes showed the similar porosity, pore size and morphology to the reference nickel cathode. The stability tests of ZnO impregnated NiO cathodes showed that the ZnO additive could dramatically reduce the solubility of NiO in a eutectic carbonate mixture …

Preparation, Characterization And Photoelectrochemical Activities Of Cu-Tio2/Ito Films, Dong Shu, Chun He, Han-Xia Zhang, Ya Xiong

Journal of Electrochemistry

Cu-TiO₂/ITO films were prepared by direct photo-reduction deposition of Cu²⁺ on TiO₂/ITO films. The nanocomposite films were characterized by UV-vis diffuse reflectance spectra (DRS), XRD spectra, Scanning Electron Microscope (SEM) technology, and photovoltage measurement. The feasibility of improving the photocatalytic activity of TiO₂ film by combining the modification of Cu nanoparticles with the application of anodic bias was investigated. The experimental results showed that the deposited Cu has an apparent enhancement effect with respect to suppressing the recombination between the photogenerated charge carriers and enhancing the photocatalytic oxidation of formic acid. The combination could …

Study On Electrochemical Properties Of Peo-Based Composite Polymer Electrolytes, Hong-Yan Du, Hu Cheng, Yong Yang

Journal of Electrochemistry

Composite polymer electrolytes were prepared by introducing nano-scale SiO₂ into PEO₈-LiClO₄ matrix. The ionic conductivity, lithium transference number and the electrochemical stability windows were measured. The phase component was evaluated with DSC techniques. The results showed that the introduction of nano fillers enhanced the ionic conductivity. It reached 4.3×10^-5 S·cm^-1 at 22 ℃. The conductivity enhancement of the composite polymer electrolytes is analyzed and proposed.

Investigation Of Adsorption And Oxidation Behavior Of Isosafrole On A Smooth Pt, Xiao-Hong Zhang, Xiao-Jing Su, Qi-Ling Zhong, Lei Zhang, De-Sheng Mei, Bin Ren, Zhong-Qun Tian

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.

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 MnO₂ (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 Mn⁴⁺ ions on the surface of EMD particles and the structural defect regions within the EMD, 2) the reduction of Mn⁴⁺ ions in ramsdellite, 3)the reduction of Mn⁴⁺ ions in pyrolusite. During the second electron discharge of EMD, the soluble Mn(Ⅲ) is reduced to Mn(Ⅱ) , …

Study On Electrochemical Performance Of Electroless Cobalt Coating For Microencapsution Of Hydrogen Storage Alloys, Tong-Chi Xia, Sheng-Li Zhang, Shu-Xin Wang, Kun Huang, Wen-Zeng Tian

Journal of Electrochemistry

The chemical cobalt plating method is used to treat on the hydrogen storage alloys. Effect of the surface treatment on the electrochemical performance of MH eletrodes was investigated by carrying out experimental methods of CV, AC and charge/discharge cycle tests. The results showed that after microencapsulation with cobalt, the impedance of electrochemical reaction on the surface and polarization during chare/discharge process was markedly decreased; and the electrocatalytic activity on the surface, discharge capacity, charge efficiency was improved. It was also indicated that the anode reaction of MH electrode treated was controlled by diffusion process.

An Electrochemical Study Of Ddtc Adsorption Jamesonite, Run-Lan Yu, Yue-Hua Hu, Guan-Zhou Qiu, Wen-Qing Qin

Journal of Electrochemistry

The interactions of jamesonite with diethyl dithiocarbamate (DDTC) were studied by AC impedance measurement and cyclic voltammetry. Several electrode processes under different potential conditions were observed. There mainly is the absorption of hydrophobic DDTC. PbD₂, S⁰ etc on the surface of jamesonite mineral from -178 mV to 472 mV (vs. SHE) and the interfacial capacitance also is small. When the electrode potential is over 472 mV, the surface of jamesonite mineral is of hydrophilicity due to the fact that hydrophobic PbD₂,S⁰ etc are oxidized into hydrophilic products such as Pb²⁺, SO_{3 …}

Electrochemical Lithium Insertion Of Nanosized Tio2, Ying Lan, Jian-Wen Liu, Xue-Ping Gao, Xing-Di Zhou, Jin-Qiu Qu, Feng Wu, De-Ying Song

Journal of Electrochemistry

The protonic titanate nanotubes with the diameter of 10～15 nm were synthesized via hydrothermal method in NaOH solution and the calcined nanotubes at 500 ℃ were transferred to anatase nanorods with the diameter of 12～20 nm due to dehydration.The electrochemical behavior of the anatase nanorods as lithium insertion materials was examined. The results showed that the nanorod electrode had the high initial discharge capacity of 232 mAh/g and second reversible capacity of 198 mAh/g. The capacity of nanorod electrode maintained 152mAh/g after 20 cycles.

Exceptional Electrochemical Activities Of Amorphous Fe-B And Co-B Alloy Particles Used As High Capacity Anode Materials, Ya-Dong Wang, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

Ultrafine amorphous alloy particles (UAAP) of Fe-B and Co-B were synthesized and tested for possible use as electroactive anode materials. It is found that unlike their parent elements, the alloy particles of transition metal (TM) and boron, the Fe-B and Co-B showed superior electrochemical activities when used as anodic materials in aqueous alkaline solution. The discharge capacities of Fe-B and Co-B electrodeswere observed to be 1200 mAh/g and 1100 mAh/g at moderately high rate of 100 mAh/g, respectively, much higher than the theoreticalcapacity of currently used zinc metal (820 mAh/g). The exceptional high capacities of the boride alloys were probably …

Structures And Redox Activities Of Poly(M-Methoxyaniline), Yun-You He, Yi-Ting Xu, Li-Zong Dai, Jean-Yves Gal, Hui-Huang Wu

Journal of Electrochemistry

Poly(m-methoxyaniline), PmMAn, was prepared in the presence of HCl, p-toluene-sulfonic acid and perchloric acid. By using cyclic voltammetry, the effect of different acid dopant on electrochemical activities of PmMAn was studied. The results showed that perchloric acid is the best acid to prepare PmMAn with good electrochemical activities The FTIR spectra indicate that the acid radical anions have embedded into PmMAn molecularchain as counter-ion during synthetic process, and this great influences the redox activities of PmMAn. SEM and XRD measurements illustrate that PmMAn is characterized by its typical molecular crystalline being monoclinic.

The Matching Study Of Electrodes In C/Ni(Oh)2 Hybrid Capacitor, Yue-Feng Su, Feng Wu

Journal of Electrochemistry

The energy storage mechanisms of electrochemical double-layer capacitor (EDLC) and C/Ni(OH)₂ hybrid capacitor had been studied. The results proved that,the difference between the capacity of EDLC and C/Ni(OH)₂ hybrid capacitor was detemined by the effectiveness usage of the activated carbon negative electrode, which is a criterion to estimate or design the theoretic capacity of the C/Ni(OH)₂ hybrid capacitor. The electrochemical availability of activated matter in Ni(OH)₂ electrode was introduced, and the quantity of the activated matter in Ni(OH)₂ electrode should be compatible with the capacity of carbon electrode. When the capacities of Ni(OH)₂ electrode …

Electrodeposition Of Copper Into Trenches Under Rotating Hydrodynamic Condition, Jian-Jun Sun, Bu-Gao Xie, Wen-Hui Yin, Guo-Nan Chen

Journal of Electrochemistry

Silicon chips patterned with treneches were fixed onto a rotating electrode. Copper was electrodeposited into the trenches under rotating hydrodynamic conditions The sizes of the trenches are 1 m in height and 0.35 m, 0.50 m and 0.70 m in width, respectively. The effects of rotating of the chip, the current density and the concentration of Cu²⁺ on the filling of thetrenches were studied. It is found that lower current density and moderate concentration of Cu²⁺ resulted in a void free filling of the trenches.

Study Of Anti-Corrosion Property On Poly(An-Co-Oas)/Epoxy, Qing-Wu Wang, Geng-Chao Wang

Journal of Electrochemistry

Polyaniline, polyanisidine and their copolymer poly(An-co-oAs) were synthesized via the solution chemical oxidative polymerization of aniline and anisidine in an acidic aqueous medium, and their properties and structure were characterized. The electrochemical method were applied to evaluate the corrosion behavior of tined iron uncoated or coated by polyaniline, poly(An-o-oAs), polyanisidine and poly(An-co-oAs)/epoxy blend in acid or saline aqueous solution. The result showed that with the increase of anisidine content, the solubility of polymers is improved apparently but their oxidation extent decreases accordingly. It is also founded that polyaniline, poly(An-co-oAs) and polyanisidine all have good anti-corrosion properties, and their anti-corrosion capacity …

Velocity And Temperature Characterization Of The First Vacuum Stage Expansion In An Inductively Coupled Plasma - Mass Spectrometer, William Neil Radicic

Theses and Dissertations

The inductively coupled plasma - mass spectrometer (ICP-MS) is the analytical instrument of choice for trace element detection and quantification. Despite the popularity of ICP-MS, significant degradation in sensitivity and precision occurs as the result of matrix and instrument-induced effects. The sources of these effects are not well understood, characterized, or correlated to particular plasma operating condition settings or matrix compositions and involve both neutral and charged species. The purpose of this study is to characterize the behavior of metastable Ar (I) atom and Ca (II) ion through the measurement of Doppler velocities and fluorescence line width "temperatures."

For the …

Evaluating The Contributions Of Desolvation And Base-Stacking During Translesion Dna Synthesis, Xuemei Zhang, Irene Lee, Anthony J. Berdis

Chemistry Faculty Publications

DNA polymerases catalyze the insertion of a nucleoside triphosphate into the growing polymer chain using the template strand as a guide. Numerous factors such as hydrogen bonding interactions, base-stacking contributions, and desolvation play important roles in controlling the efficiency and fidelity of this process. We previously demonstrated that 5-nitro-indolyl-2′-deoxyriboside triphosphate, a non-natural nucleobase with enhanced base-stacking properties, was more efficiently inserted opposite a non-templating DNA lesion compared to natural templating nucleobases (E. Z. Reineks and A. J. Berdis, Biochemistry, 2004, 43, 393–404). The catalytic enhancement was proposed to reflect increased base-stacking interactions of the non-natural nucleobase with the polymerase and …

N9 Alkylation And Glycosylation Of Purines; A Practical Synthesis Of 2-Chloro-2'-Deoxyadenosine, Minghong Zhong

Theses and Dissertations

(a) The Robins reagent [2-acetamido-6-O-(diphenylcarbamoyl)purine] was utilized for glycosylation under Lewis acid conditions. Regioselectivity of glycosylation depends on the glycosyl donor and its 2-O- or 2-N-protecting group. Regioselective N9 glycosylation of 2-acetamido-6-O-(diphenylcarbamoyl)purine with problematic glucosamine has been accomplished by protecting the amino function as a phthalimido group with consequent stabilization of the oxocarbenium cation, and lowering the activation energy by introduction of trichloroacetimidate at the anomeric carbon.

(b) 6-Heteroaryl functions [6-(1,2,4-triazol-4-yl) and 6-(imidazol-1-yl)] were introduced into purine derivatives for regioselective N9 alkylation. The regiospecificity of alkylation mainly results from steric effects due to the coplanar conformation of the two linked …

Structures And Stability Of Medium Silicon Clusters. Ii. Ab Initio Molecular Orbital Calculations Of Si12–Si20, X.-L. Zhu, Xiao Cheng Zeng, Y.A. Lei, B. Pan

Xiao Cheng Zeng Publications

Ab initio all-electron molecular-orbital calculations are carried out to study the structures and relative stability of low-energy silicon clusters (Si_n , n=12– 20). Selected geometric isomers include those predicted by Ho et al. [Nature (London) 392, 582 (1998)] based on an unbiased search with tight-binding/genetic algorithm, as well as those found by Rata et al. [Phys. Rev. Lett. 85, 546 (2000)] based on density-functional tight-binding/single-parent evolution algorithm. These geometric isomers are optimized at the Møller–Plesset (MP2) MP2/6-31G(d) level. The single-point energy at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d …

Electrochemical Separation Of Curium And Americium, David W. Hatchett, Kenneth Czerwinski

Separations Campaign (TRP)

The objective of this project is to develop a method for the separation of Am from Cm based on electrochemical techniques. Electrochemical systems that allow the thermodynamics of actinide and lanthanide complexes to be systematically evaluated and tuned will be examined. The influence of complex formation on the ability to selectively isolate a given species electrochemically will be evaluated. Metal-ligand complex formation provides a useful derivation technique to increase solubility in solution environments that favor precipitation. In addition, the thermodynamic properties of a complex relative to the isolated species may be shifted to more suitably measurable electrochemical separation regimes. Electrochemical …

Fundamental Chemistry Of U And Pu In The Tbp-Dodecane-Nitric Acid System, Kenneth Czerwinski, Byron Bennett

Separations Campaign (TRP)

The speciation of hexavalent U and tetravalent Pu will be examined in the TBP-dodecane-nitric acid systems. This topic is chosen based on data needs for separation modeling identified by the AFCI. Emphasis will be placed on studying the influence of nitrate and acetohydroxamic acid on U and Pu speciation as well as conditions where a third phase forms in the organic phase. The organic phase will be 30% TBP in dodecane. Equal volumes of aqueous and organic phase will be used. The speciation of the actinides in the aqueous and organic phase will be determined by a number of different …

Chemical Analyses For Alcove 8/Niche 3 Tracer Studies, Jeanette Daniels, Klaus J. Stetzenbach, Drew Coleman, Don Baepler, Amy J. Smiecinski

Publications (YM)

The objective of this task “Analytical Support For Tracer Studies in Alcove 8 / Niche 3” is to provide chemical analyses for the tracer studies at Alcove 8 / Niche 3 in the Exploratory Studies Facilities (ESF). This analytical support includes developing procedures for measuring tracer concentrations and then performing the tracer (and other background constituent) analyses for the water samples generated from each Alcove 8 / Niche 3 tracer test. These tracer tests are part of the Flow and Seepage Testing in Alcove 8/Niche 3 (TWP-NBS-HS-000004 REV 00). The overall goal of this study is to quantify large scale …

Experimental And Theoretical Studies On The Pharmacodynamics Of Cisplatin In Jurkat Cells, Kirk A. Tacka, Dava Szalda, Abdul-Kader Souid, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

For Jurkat cells in culture exposed to cisplatin (1), we measured the number of platinum adducts on DNA and showed that it is proportional to the AUC, the area under the concentration vs time curve, for cisplatin. The number of platinum-DNA adducts is measured immediately following exposure to drug. The AUC is calculated either as the product of the initial cisplatin concentration and the exposure time or as the integral under the concentration vs time curve for the unreacted dichloro species, which decreases exponentially. We also show that the number of adducts correlates with decreases in respiration, with the amount …

Large-Scale Expression And Purification Of Gst-Caveolin Fusion Proteins, Deidre L. Carroll

McCabe Thesis Collection

In this thesis, I will discuss the study I conducted from June 2, 2003 to July 31, 2003 at the University of Oklahoma Health Sciences Center Dean A. McGee Eye Institute, facilitated by Dr. Michael Elliott, funded by the Undergraduate Biomedical Education Program at Langston University, expressing and purifying GST-Cav~olin fusion proteins on a large-scale. Caveolins are the principle constituents of caveolae. Caveolae are flask-shaped invaginations of the plasma membrane. Caveolae are most abundant in endothelial cells, fibroblasts, and myocytes (Smart et al. 1999). These structures participate in three main areas of cell physiology: endocytosis (Henley et al. 1999), cholesterol …

Infrared Spectrum And Stability Of A Π-Type Hydrogen-Bonded Complex Between The Oh And C2h2 Reactants, James B. Davey, Margaret E. Greenslade, Mark D. Marshall, Marsha I. Lester, Martyn D. Wheeler

Chemistry

A hydrogen-bonded complex between the hydroxyl radical and acetylene has been stabilized in the reactant channel well leading to the addition reaction and characterized by infrared action spectroscopy in the OH overtone region. Analysis of the rotational band structure associated with the a-type transition observed at 6885.53(1) cm−1 (origin) reveals a T-shaped structure with a 3.327(5) Å separation between the centers of mass of the monomer constituents. The OH (v = 1) product states populated following vibrational predissociation show that dissociation proceeds by two mechanisms: intramolecular vibrational to rotational energy transfer and intermolecular vibrational energy transfer. The highest observed OH …

Cesium Effect: A Mild And Efficient Synthesis Of Secondary And Tertiary Phosphines, Matthew Honaker

Masters Theses & Specialist Projects

A mild and efficient method to synthesize a variety of secondary and tertiary, as well as disecondary and ditertiary phosphines has been developed. Using reaction conditions that include cesium hydroxide, molecular sieves, and DMF, at room temperature, a wide range of alkyl halides has been coupled to primary or secondary phosphines to yield secondary or tertiary phosphines. Included were activated and aliphatic halides, as well as base sensitive functional groups. In addition, examples of disecondary and ditertiary ligands have also been prepared using similar reaction conditions. The synthesis of a P-N-P ligand was also accomplished with these procedures. Optically active …

Directed Ortho Metalation In Hydrocarbon Solvents: Opposing Pi-Resonance Effects, Barry Woosley

Masters Theses & Specialist Projects

Hydrocarbon solvents are known to be unreactive toward organolithium reagents and do not typically support ortho-metalation reactions without the aid of a promoter. An exception would be an arene substrate having the capability to bidentate complex to the reactive alkyllithium dimer, which enables ortho-metalation to occur in high yields. A second, more limiting exception, would be that the arene substrate possesses localized lone pairs of electrons, as is the case when the directed ortho metalating group (DMG) is located in the benzyl position. The work reported here centers upon developing a third and larger class of arene substrates that are …

Spectroscopic Studies Of Chlorophyll A Complexes With Trinitro-Substituted Flourene Derivatives, Stephanie Smalley

Masters Theses & Specialist Projects

Absorption, fluorescence, and excited-state lifetime studies of chlorophyll a (Chl a) with fluorene, 2-(2,4,7-Trinitro-fluoren-9-ylideneaminooxy)-propionic acid (TFPR), 2- (2,4,7-Trinitro-fluoren-9-ylidenemethyl)-phenol, (TFPH), and 9-Isopropylidene-2,4,7- trinitro-9H-fluorene (ITNF) have been investigated. These systems were studied in acetonitrile and dichloromethane at room temperature. Absorption data were analyzed with the Nash plot. Linearity of the Nash plots proved that a 1:1 complex was formed between the donor and acceptor. Ground state binding constants (Ka) of each system were also determined from the y-intercept of these plots. Fluorescence data were analyzed with a Stern-Volmer plot. The quenching constants (Ksv) were obtained from the slope of these plots. These …