Chemistry Commons^™

Covalent Bonds In Superconducting Rapid Cooled Alloys: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9 Detected By Local Atomic Enhanced Xrd, J. Kmiec, K. Tyson, Juana Acrivos, D. Gulamova, J. Chigvinadze

Faculty Publications, Chemistry

High temperature layer superconducting cuprates (HTLSC) alloys: (Bi1.7Pb0.3Sr2Can-1CunO2n+4+δ)2,n=1-9 called (2s:2:n-1:n) prepared in Uzbekistan from melts in concentrated sun flux, followed by rapid cooling, SFQA technology that preserves melt tiling by confinement of conduction layer: |(CuO2)1/2|Ca|(CuO2)1/2]n-1| in the hard shell ||, of the n=1 phase,[(CuO2)1/2|SrO|Bi1.7Pb0.3O|Bi1.7Pb0.3O|SrO|(CuO2)1/2]2. Disproportion leads to different n-phase mixing, and periodic lattice distortions (PLD) through bond resonance covalent crystalaxes: 2(rCu+2+rO-2)=4.2Å>a=3.82Å>d(CuO)+2-3/2d(O3))=3.2Å≈(cn-c1)/2(n-1). Individual phase local bonds Cu-Ca, Cu-Sr, Cu-O-Cu are ascertained by X-Ray diffraction near Cu K-edgefollowed by Cu-Ca bond scattering. The HTLSC density, ρ decrease as n increases obtains Tc,n ~180 K, identified due to n=8 phase on …

NaXMYFe(Cn)6(M=Fe, Co, Ni): A New Class Of Cathode Materials For Sodium Ion Batteries, Jiang-Feng Qian, Min Zhou, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

Three types of Prussian blue compounds, Na_xM_yFe(CN)₆ (M = Fe, Co, Ni), were prepared simply by solution precipitation method and tested as cathode materials for sodium-ion batteries. X-ray diffraction and SEM measurements demonstrated that the prepared materials, namely, NaFeFe(CN)₆, Na₂CoFe(CN)₆, and Na₂NiFe(CN)₆, exhibited a perfect cubic structure with a particle size of several tens nanometers. Cyclic voltammetric and galvanostatic cycling tests revealed very different electrochemical behaviors of these three materials. The specific capacities of NaFeFe(CN)₆ and Na₂CoFe(CN)₆ could reach 113 mAh·g …

Template-Free Synthesis Of Porous Nio Hierarchical Structure For High Performance Supercapacitors, Yun Huang, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

A facile and template-free hydrothermal method is proposed to successfully synthesize porous NiO hierarchical structure, which is found to be assembled from ultrathin NiO nanosheets. As for electrochemical pseudocapacitor application, the obtained material exhibits not only high specific capacitances of 435 F·g^-1 at 20 mV·s^-1 and 367 F·g^-1 at 10 A·g^-1, but also holds a good electrochemical stability over 1000 cycles at a current rate of 20 mV·s^-1. These results suggest that the hierarchical structured porous NiO is a promising supercapacitor electrode material.

Intercalation/Deintercalation Reaction Of Olivine-Type Phosphate, Jun Wu, Zhi-Hu Li, Qun Wu, De-Cheng Li, Jun-Wei Zheng, Yan-Hui Xu

Journal of Electrochemistry

In the present work the rate-limited step during Li intercalation/deintercalation processes for olivine-type phosphate has been discussed. It is found that the increase in the carbon content is effective to improve the electrode capacity and the electrochemical activity of the Mn element in the active materials. It is also found that the asymmetric phenomenon exists in the charge-discharging curves, especially when the carbon content is low. During charging the Fe²⁺/Fe³⁺ the plateau capacity is much less than the corresponding theoretical capacity, while the capacity that corresponds to Co²⁺/Co³⁺ couple is more than the theoretical …

Electrochemical Preparation Of Nanostructural Pt-Ni And Pd-Ni Films For Ethanol Electro-Oxidation, Chen-Zhong Yao, Hui-Xuan Ma, Bo-Hui Wei

Journal of Electrochemistry

The Pt-Ni and Pd-Ni films were successfully prepared on Ti substrates by electrodeposition method. The porous Pt-Ni nanoflakes appeared to be uniform with the thickness of the slices about 10 ~ 20 nm. The porous Pd-Ni nanoparticles with a flower shape appeared to be uniform with the diameters of 50 ~ 60 nm. The XRD patterns also indicated that the Pd-Ni and Pt-Ni nanostructures have the poor crystallinity. The onset potentials of ethanol oxidation were negatively shifted to –0.74 V on Pt-Ni electrodes and –0.71 V on Pd-Ni electrodes, respectively. Addition of Ni could enhance catalytic activities and antitoxic properties …

Electrochemical Properties Of The Keggin-Type Lacunary Heteropolysilicate Anion And Its Eectrocatalysis For H2O2 Reduction, Xi-Long Liu, Chun-Yan Wu, Fang Zhou, Hong-Sheng Liu, Ying-Jie Hua, Chong-Tai Wang, Xiao-Yang Liu

Journal of Electrochemistry

Electrochemical properties of the Keggin-type lacunary heteropolysilicate anion SiW₁₁O₃₉^8- (SiW₁₁) and its indirect electrocatalysis for H₂O₂ reduction in the supporting electrolyte containing 0.1 mol·L^-1 NaHSO₄ and Na₂SO₄ solutions were investigated using cyclic voltammetry, square wave voltammetry and alternating current impedance spectroscopy. Experimental results indicated that SiW₁₁ showed two pairs of reversible redox waves on the glassy carbon (GC) electrode in an acidic solution. The electron transfer number corresponding to the two pairs of waves was one, and the proton transfer number involved was two during …

Electrochemical Reduction Of Co2 On Sn/Cu Electrodes, Chen-Chen Zhao, Jian-Wei Guo, Li Wang, Xiang-Ming He, Cheng Wang, Zhi-Xiang Liu

Journal of Electrochemistry

The Sn/Cu electrodes were prepared by electroplating method and their morphologies under different galvanization current densities were determined by SEM. In alkali, the effects of Sn/Cu electrodes on the activities towards hydrogen evolution and electrochemical reduction of CO₂ were investigated in alkaline solutions using a three-electrode system. These results indicated that the Sn/Cu electrodes prepared at 10 mA/cm² and 15 mA/cm² showed good activities, while that prepared at 15 mA/cm² was even better in activities. The synergetic structure of the Sn/Cu electrode to be beneficial to electrochemical reduction of CO₂ has been pointed out.

Ethanol Electrooxidation On Pt/Mo2/Cnts Catalysts, Yu-Long Cheng, Jie Sun, Ji-Gang Li, Li-Gong Zhang, Tian Zhou, Geng Chang, Zhong-Chao Dong

Journal of Electrochemistry

The ethanol electrooxidation behaviors on Pt/MO₂/CNTs（M=Sn, Ti, Ce）and Pt/CNTs catalysts in H₂SO₄ solutions were researched by cyclic voltammetry. It has revealed that the catalysts with the addition of metal oxides presented higher electrooxidation activity for ethanol, in particular, the Pt/CeO₂/CNTs catalyst showed the best activity for ethanol electrooxidation intermediate. The Pt/SnO₂/CNTs catalyst demonstrated the best ethanol electrooxidation activity when considering the synthetic effects of such parameters as the onset oxidation potential, peak current densities and total oxidation area.

Electrochemical Performances Of Carbon-Coated Na2Ti6O13 Nanotubes, Guo-Ran Li, Shuai Sun, Xue-Ping Gao

Journal of Electrochemistry

With rutile TiO₂ and NaOH as starting materials, the Na₂Ti₆O₁₃ nanotubes were prepared by a hydrothermal reaction. The carbon-coated Na₂Ti₆O₁₃ nanotubes were obtained by treating the Na₂Ti₆O₁₃ nanotubes for 4 h in glucose aqueous solutions containing 0.1 mol·L^-1 NaOH. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microcopy (TEM). The results showed that the dimensions of carbon-coated Na₂Ti₆O₁₃ nanotubes were 14 ~ 19 nm of outer diameter, 2 ~ 5 …

Corrosion Inhibition Of 316l Steel Using Sodium Diethyl Dithiocarbamate Solution In Simulated Crude Oil, Xiao-Guang Ren, Jie Yang

Journal of Electrochemistry

The corrosion inhibition behaviors of 316L steel using the sodium diethyl dithiocarbamate (SDDTC) compound in the crude simulation solution were studied in the absence and presence of zinc sulfate or sodium chromate with different compositions. Experiment resultss showed that in the environments of highly acidic and high concentrations of chloride ions the SDDTC compound could well inhibit the corrosion of 316L steel. The good synergic effects on the corrosion inhibition of 316L steel by additions of either zinc sulfate or sodium chromate into SDDTC compound were indicated in this study, which is of great significance and importance in practical applications.

Electrochemical Study Of Protein Modification, Jing Zhao, Xiao-Li Zhu, Gen-Xi Li

Journal of Electrochemistry

Protein post-translational modification is a key physiological procedure, which has received more and more research interests from the scientists not only in protein science but also in some other fields. The usually employed techniques for the study of protein modification include mass spectrum, affinity chromatography, etc. Considering the complexity of protein modification and the urgent demand of such kind of study, it is highly required to develop new techniques to perform more studies. Electrochemical methods, which have been widely used in chemical study and analysis, are playing an increasingly important role in many fields of biological studies. The modification of …

Preparation And Electrochemical Performance Of Mo-Doped Li3V2(Po4)3/C Cathode Materials, Zhi-Yuan Tang, Wei Yuan, Ji Yan, Wen-Feng Mao, Li Ma

Journal of Electrochemistry

The molybdenum-doped Li₃V_2-xMo_x(PO₄)_3/C (x = 0.01, 0.02 and 0.03) cathode materials were prepared with a sol-gel method by using Li₂CO₃, NH₄H₂PO₄, V₂O₅ and MoO₃ as raw materials, and citric acid as both chelating reagent and carbon source. The X-ray diffraction (XRD) analyses showed that the crystal structure of as-prepared samples is monoclinic with space group P2₁/n. Scanning electron microscopy (SEM) observations indicated the uniform morphology for Li₃Mo_0.02V_1.98(PO₄) …

Synthesis Of Lini0.5Co0.2Mn0.3O2 For Lithium Ion Batteries And The Mechanism Of Capacity Fading At High Temperature, Wen Liu, Miao Wang, Ji-Tao Chen, Xin-Xiang Zhang, Heng-Hui Zhou

Journal of Electrochemistry

The Ni-rich cathode materials, LiNi_0.5Co_0.2Mn_0.3O₂, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh·g^-1 in the 3.0~4.4 V at 0.2C. However, at 55 °C the LiNi_0.5Co_0.2Mn_0.3O₂ experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi_0.5Co_0.2Mn_0.3O₂ cycled at high temperature in range of high-voltage charge and …

Synthesis And Electrochemical Properties Of Lifeso4F/Graphene Composite As Cathode Material For Lithium-Ion Batteries, Wei Guo, Ya-Xia Yin, Li-Jun Wan, Yu-Guo Guo

Journal of Electrochemistry

The LiFeSO₄F was successfully synthesized from the reactions of FeSO₄∙xH₂O (x=1, 4, 7) with LiF in tetraethylene glycol media through a facile low temperature method. The structures and microscopic features of the products were characterized by XRD, SEM and TEM. TGA result shows the good thermal stability of the as-prepared LiFeSO₄F. No diffraction peaks of the FeSO₄ are observed in the as-prepared products with the starting material of either FeSO₄∙4H₂O or FeSO₄∙7H₂O, which should be ascribed to delaying the release of H_{2 …}

Synthesis And Electrochemical Properties Of Yttrium-Doped Lini0.49Mn1.49Y0.02O4, Xian-Wen Zhang, Zheng-Xi Zhang, Li Yang, Shao-Hua Fang, Long Qu

Journal of Electrochemistry

The LiNi_0.49Mn_1.49Y_0.02O₄ cathode material was synthesized using the citric acid-assisted sol-gel method by partial substitutions of Ni and Mn with Y in the LiNi_0.5Mn_1.5O₄ material. The influences of Y doping on the structure and electrochemical properties were investigated by means of X-ray diffraction, cyclic voltammetry, galvanostatic charge/discharge tests and AC impedance spectroscopy. The results showed that the introduction of Y into the LiNi_0.5Mn_1.5O₄ greatly improved the cycle performance and rate capability. When the charge and discharge current was 1 C in the potential …

Catalytic Activities Of Electrochemically Dealloyed Pt(Pd)-Cu Catalysts For Oxygen Reduction Reaction, Rui-Zhi Yang, Strasser Peter, Toney Michael

Journal of Electrochemistry

The electrochemically dealloyed Pt(Pd)-Cu catalysts were prepared by electrochemical dealloying of Cu₃Pt(Pd) and their catalytic activities toward oxygen reduction reaction (ORR) were studied in 0.1 mol·L^-1 HClO₄ . solutions. The structural features of the dealloyed Pt(Pd)-Cu were revealed by synchrotron-based anomalous X-ray diffraction (AXRD) and surface X-ray scattering (SXS) at an atomic scale. We established a relationship between the structure and the catalytic activity by comparing the ORR activity and the structure of dealloyed Cu₃Pt nanoparticles with similarly dealloyed Cu₃Pt thin films and Cu₃Pt(111). The enhancement in the activity of …

Electrocatalytic Oxidation Of Ethanol On Ni-P-Tio2 Composite Coating Electrodes, Guang-Hui Hu, Hai-Xia Zeng, Zhi-Gang Wei, Zhan-Chang Pan, Shu-Guang Xie, Yan-Di Zou

Journal of Electrochemistry

The Ni-P-TiO₂ composite coating electrodes with different contents of TiO₂ particulates were prepared by electroless plating technique from Ni-P plating bath containing TiO₂ powders on brass. Cyclic voltammetry, linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were used to test the electrochemical performance of Ni-P-TiO₂/Cu electrodes. It was indicated that the Ni-P-TiO₂/Cu electrodes exhibited very strong electrocatalytic activity toward the oxidation of ethanol in alkaline medium at ambient temperature. The electrocatalytic activity of ethanol oxidation on the Ni-P-TiO₂ electrodes depended on the amounts of TiO₂ in the coatings. The …

An Examination Of Oxidative Passivated Surfaces On 19th Century Colt Revolver Barrels, Mckenzie Allison Floyd

Scripps Senior Theses

Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to examine a series of six revolver barrels manufactured by the Colt Patent Arms Manufacturing Company between 1853 and 1863. SEM micrographs revealed a vast range of surface morphologies among the corroded samples. XRD diffraction patterns showed varying levels of magnetite on the blackened samples, but hematite could not be identified. EDS was used to map elemental distribution and quantify elemental abundances on the gun surfaces; further investigation using this technique may reveal more definitive information on whether some elements present were deposited during patination.

Variability Of Black Carbon Deposition To The East Antarctic Plateau, 1800-2000 Ad, M. M. Bisiaux, R. Edwards, J. R. Mcconnell, M. R. Albert

Dartmouth Scholarship

Refractory black carbon aerosols (rBC) from biomass burning and fossil fuel combustion are deposited to the Antarctic ice sheet and preserve a history of emissions and long-range transport from low- and mid-latitudes. Antarctic ice core rBC records may thus provide information with respect to past combustion aerosol emissions and atmospheric circulation. Here, we present six East Antarctic ice core records of rBC concentrations and fluxes covering the last two centuries with approximately annual resolution (cal. yr. 1800 to 2000). The ice cores were drilled in disparate regions of the high East Antarctic ice sheet, at different elevations and net snow …

Communication: Adjusting Charge Transfer State Energies For Configuration Interaction Singles: Without Any Parameterization And With Minimal Cost, Xinle Liu, Shervin Fatehi, Yihan Shao, Brad S. Veldkamp, Joseph Subotnik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In a recent article, we showed that configuration interaction singles (CIS) has a systematic bias against charge-transfer (CT) states: CT vertical excitation energies are consistently too high (by 1-2 eV) as compared with non-CT energies [J. E. Subotnik, J. Chem. Phys. 137, 071104 (2011)]. We now show that this CIS error can be corrected approximately by performing a single Newton- Raphson step to reoptimize orbitals, thus establishing a new set of orbitals which better balances ground and excited state energies. The computational cost of this correction is exactly that of one coupled-perturbed Hartree-Fock calculation, which is effectively the cost of …

The Synthesis Of A Homologous Series Of Alkyl Lumazines And Their Application To The Dispersion Of Carbon Nanotubes, William P. Kopcha

Master's Theses

In this thesis, the synthesis of a series of alkyl lumazine surfactants (LC_n) is reported. Their application to the dispersion of both CoMoCAT and HiPco single-walled carbon nanotubes (SWNTs) is examined in detail and the thermal stability and chirality selection properties of dispersions made with these surfactants were compared both between themselves and with an alkyl flavin surfactant (FC₁₂). Lumazine alkyl chain length exhibited some control over the quality and the quantity of SWNTs dispersed. LC₁₀ was deemed most appropriate for comparison with FC₁₂ based on considerations of solubility and nanotube individualization. …

Synthesis Of Some Aminopicolinic Acids, Alicia Beatty, Ramadan Bawa

Chemistry & Biochemistry Faculty Works

Some aminopicolinic acid derivatives have been synthesized and fully characterized. These pyridine derivatives were 4-aminopicolinic acid, 4-(4-aminophenylethynyl) picolinic acid and 4-(3-aminophenylethynyl) picolinic acid. In addition to these compounds, other substituted picolinic acids were made throughout the synthetic paths.

Investigation Of Saccharide Release Through Acidification, Sonication, Thermal, And Microwave Treatments, William K. Storck

Honors Theses

With diminishing fossil fuels, renewable sources are becoming much higher in demand. Algae are becoming an increasingly important source of biofuels. Production of biofuels from algae exceeds yields from every other source, most notably corn, per acre. It also provides a highly viable method of reusing carbon dioxide and does not compete with other crops for growth. The production of ethanol through fermentation requires the release of saccharides produced by the algae. The more saccharides extracted, the more ethanol can be produced. This project investigates for a more effective method of maximum saccharide release.

The purpose of this project is …

Toxicity Of Tio₂ Nanoparticles In The Genomic Dna Of Cucurbita Pepo, Fabiola Moreno-Olivas^, Vincent Gant, Isaac Montes, Hiram Castillo-Michel, Kyle L. Johnson, Jose R. Peralta-Videa, Jorge L. Gardea-Torresdey*

COURI Symposium Abstracts, Spring 2012

The nanomaterial industry is growing very fast and nanoparticles (NPs) are used in variety of instruments and goods. NPs can reach the plants through different manners; though, little is known about their impact on food crops and the possible effects in the food chain are unknown. In this research, the possible genotoxic effects of TiO₂ NPs on zucchinis (Cucurbita pepo) were studied. Seven-day old hydroponically grown zuchinnis plants were treated for 7 days with TiO₂ NPs suspended in the nutrient solution at concentrations varying from 0 to 50 mg/L. Random amplified polymorphic DNA assay was performed and showed the …

Soil Buffering Mechanisms, Ken Overway, Hillary Rees

Chemistry Faculty Scholarship

The effect acid rain has on soil is dependent on the mineral content. This effect varies based on the mineral systems which can buffer the pH of the soil once exposed to the acid rain. Calcareous minerals (reaction 1), silicate clays (reaction 2), and aluminosilicate clays (reaction 3) are the three mineral systems that provide soil the capacity to withstand acid attack before a major pH drop occurs. One way to differentiate between these systems could be to observe the reaction orders of the underlying mechanisms.

CaCO₃(s) 2 H⁺(aq) ⇌ Ca2+(aq) + H₂O(l) + …

The Role Of Hsp70 In Cancer: A Study Of The Hsp70 / Akt Relationship, John Koren

USF Tampa Graduate Theses and Dissertations

The Hsp70 family of molecular chaperones is essential for

protein folding, re-folding misfolded client proteins, clearance

of aberrant client proteins, and can also inhibit programmed

cell death. There are two major cytosolic members of this

family: the constitutive Hsc70, and the inducible Hsp72. Under

stress conditions the Hsp70 family protects the cell from

protein related damage by the induction of Hsp72. Hsc70 and

Hsp72 are highly homologous with minor differences in

substrate binding. In cancers, Hsp72 is commonly induced and

this induction is thought to aid in cancer cell survival. In these

studies we demonstrate the differential regulation of the …

Interaction Of Pharmaceutical Compounds With Dissolved Organic Matter, Carlen Nigl Smith

Honors Theses

Highly prescribed pharmaceutical compounds and their metabolites used to treat conditions ranging from infections to depression are of environmental concern as these excreted compounds are increasingly appearing in wastewater influent. As pharmaceuticals enter treatment plants they also can interact with dissolved organic matter (DOM) present. This potential interaction between pharmaceutical compounds and DOM may inhibit the advanced oxidation process (AOP) based removal of drugs during water treatment. The focus of this research was to utilize multinuclear magnetic resonance and hydroxyl radical kinetics to assess whether an interaction between influent pharmaceuticals and DOM does occur, the extent of the interaction, and …

Synthesis Of Some New Fluorinated Hexahydroquinoline And Acridinedione Derivatives In Trifluoroethanol, Cosmas O. Okoro, Mumiye A. Ogunwale, Tasneem Siddiquee

Chemistry Faculty Research

This article describes one-pot synthesis of new fluorinated hexahydroquinoline derivatives via unsymmetric Hantzsch reaction involving 5-trifluoromethyl-1,3-cyclohexanedione, aldehydes, acetoacetate ester, and ammonium acetate in trifluoroethanol (TFE). The reaction is simple and rapid with high yield.

2-Allylphenyl Glycosides As Complementary Building Blocks For Oligosaccharide And Glycoconjugate Synthesis, Hemali Premathilake, Alexei Demchenko

Chemistry & Biochemistry Faculty Works

The O-allylphenyl (AP) anomeric moiety was investigated as a new leaving group that can be activated for chemical glycosylation under a variety of conditions, through both direct and remote pathways. Differentiation between the two activation pathways was achieved in a mechanistic study. The orthogonal-type activation of the AP moiety along with common thioglycosides allows for the execution of efficient oligosaccharide assembly.

Establishment Of An Efficient Method For The Synthesis Of Srh, An Important Molecule In Bacterial Quorum Sensing, Emily Showell-Rouse, Ruoyi Liu

Creative Activity and Research Day - CARD

Quorum sensing (QS) is a process of bacterial communication that regulates the expression of virulence genes in many bacteria. The study of QS, could lead to new treatments for bacterial diseases. Interspecies bacterial communication utilizes the signaling molecule autoinducer-2 (AI-2). The LuxS enzyme converts S-ribosyl-L-homocysteine (SRH) into 4(S),5-dihydroxypentane-2,3-dione (DPD), the precursor of AI-2. LuxS inhibitors could prevent QS by halting conversion of SRH. We have developed an efficient synthesis of SRH from D-ribose and L-homocystine. This procedure provides us with both a supply of SRH for biochemical assays and a foundation for the synthesis of SRH analogs …