Physical Chemistry Commons^™

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 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.

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 …

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.

Synthesis And Theoretical Studies Of Pyridyl Fullerene Derivatives For Supramolecular Applications In Photovoltaic Systems, Robert Vina-Marrufo ^, Danisha M. Rivera-Nazario, Agustin Molina-Ontoria, Luis Echegoyen *

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Proton-Coupled Electron Transfer (Pcet) With Bimetallic Systems, Maripaz A. Calderon ^, Dino Villagran *

COURI Symposium Abstracts, Spring 2012

Electron-transfer (ET) is one of the simplest chemical events, yet, it is a vital process for chemical reactivity. Proton-coupled electron transfer (PCET) is the concerted transfer of protons and electrons which is fundamental in chemical and biological systems and processes in electrochemistry, photosynthesis, and enzymatic activity. Similarly, mixed-valence (MV) systems are pervasive in nature and provide a platform for multiple electron transfers systems in nature. While both fields have been studied extensively, little work has been done on the intersection of the two. This project explores the elegant use of MV bimetallic systems through hydrogen bonded networks. A variety compounds …

Bon-Bons: Cyclic Molecules With A Boron-Oxygen-Nitrogen Backbone. Computational Studies Of Their Thermodynamic Properties, Aloysus K. Lawong, David W. Ball

Chemistry Faculty Publications

Although they were first reported in 1963, molecules with a boron-oxygen-nitrogen dimeric backbone do not seem to have been investigated seriously in terms of thermodynamic properties. Here we report on the calculated structures and properties, including thermodynamics, of several so-called “BON-BON” molecules. With the popularity of nitrogen-containing substituents on new high-energy materials, nitro-substituted BON-BONs were a focus of our investigation. A total of 42 BON-BON molecules were evaluated, and thermochemical analysis shows a decrease in the specific enthalpy of combustion or decomposition with increasing NO₂ content, consistent with other systems.

Towards One Key To One Lock: Catalyst Modified Indium Oxide Nanoparticle Thin Film Sensor Array For Selective Gas Detection, Kun Yao, Daniela Caruntu, Sarah Wozny, Rong Huang, Yumi H. Ikuhara, Baobao Cao, Charles J. O'Connor, Weilie Zhou

Advanced Materials Research Institute (AMRI)

Homogeneous In2O3 nanoparticles (NPs) were self-assembled into thin film sensor arrays on a single chip, with further surface modification by noble metal catalysts. The NP film sensor arrays show clear current responses when exposed to different target gases, and both sensitivity and selectivity were greatly improved. Particularly, the sensors modified with Au, Pd, and Pt nanocatalysts demonstrated higher sensitivity to H2S, H-2 and CO, respectively, making the gas discrimination direct and simple, like "one key to one lock". The particle size dependence of the noble metal modifiers to the sensitivity was further investigated by tuning the sputtering parameters. Three different …

K-Shell X-Ray Spectroscopy Of Atomic Nitrogen, M. M. Sant'anna, Gunnar Ohrwall, Wayne C. Stolte, Alfred S. Schlachter, Dennis W. Lindle, B. M. Mclaughlin

Chemistry and Biochemistry Faculty Research

Absolute K-shell photoionization cross sections for atomic nitrogen have been obtained from both experiment and state-of-the-art theoretical techniques. Because of the difficulty of creating a target of neutral atomic nitrogen, no high-resolution K-edge spectroscopy measurements have been reported for this important atom. Interplay between theory and experiment enabled identification and characterization of the strong 1s → np resonance features throughout the threshold region. An experimental value of 409.64 ± 0.02 eV was determined for the K-shell binding energy.

The Electrocatalytic Study Of Licoo2 In Air Electrode For Lithium-Air, Jun Gao, Wei Wu, Yan-Yan Tian, Yong Yang

Journal of Electrochemistry

The LiCoO₂ has been investigated as a new electrocatalyst for air electrodes using homemade lithium-air battery. The electrochemical performance and structural changes of the LiCoO₂ based composite air electrodes have been studied. The results of CV, XRD and charge-discharge tests show that the composite air electrodes composed of LiCoO₂ can greatly improve the discharge performance of lithium-air batteries. In particular when the composite air electrodes are charged to 4.1 V before further discharging, the obvious catalytic effects of LiCoO₂ are attributed to higher valence state of the Co element in LiCoO₂, esp. at charged …

Electrochemical Characterization Of (Phmgcl)2-Alcl3/Mixed Ether Electrolytes, Fei-Fei Wang, Yong-Sheng Guo, Jun Yang, Li-Yan-Na Nu, Jiu-Lin Wang

Journal of Electrochemistry

The (PhMgCl)₂-AlCl₃ salts were prepared and the electrochemical properties of (PhMgCl)₂-AlCl₃ electrolytes containing dimethoxyethane(DME)+THF, Diglyme(DG)+THF and Tetraglyme(TG)+THF solvents with different proportions on various metal electrodes were studied. Compared with (PhMgCl)₂-AlCl₃/THF, the (PhMgCl)₂-AlCl₃/DG+THF(3:2) solvents showed high ionic conductivity of 1.605×10^-3 S·cm^-1, good reversible Mg deposition behavior and anodic anti-oxidation performance with an electrochemical window wider than 2.8 V. In addition, the DG+THF mixed solvent could greatly lower the saturated vapor pressure by reducing from 23.46 kPa to 9.41 kPa, which suppresses volatilization of the …

Electrocatalytic Study Of Pseudomonas Aeruginosa Bte-1 Strain, Ping Zhou, En-Ren Zhang, Li Zhou, Guo-Wang Diao, Jun-Le Niu

Journal of Electrochemistry

The aim of the present study is to investigate the electrocatalytic activity of electricity-producing Pseudomonas aeruginosa BTE-1 strain under anaerobic conditions. Pseudomonas aeruginosa BTE-1 was inoculated into anaerobic three-electrode electrochemical cells, and the electrocatalytic activity was measured at poised potentials. HPLC and cyclic voltammetry were used to detect potential electron mediators in solutions. Experimental results showed that no detectable pyocyanine was excreted by P. aeruginosa BTE-1 strain in the anaerobic electrochemcial cells, and P. aeruginosa BTE-1 exhibited direct electrocatalytic activity through the formation of biofilm on the electrode surface which was induced by the electron transfer from the cells of …

Cycle Lifetime Investigation Of Nickel Electrode Prepared By Electrochemical Impregnation For Applications In Aerospace Nickel Hydrogen Cells, Hai-Chang Zhang, Li-Xin Tan, Cheng Guo, Wen-Cheng Ming, Xue-Ying Ren

Journal of Electrochemistry

In this paper, the effects of overcharge, charge-discharge C rate and pore size on cycle lifetime of 4.5’ electrochemical impregnated nickel electrode were investigated. In the case of the electrode was overcharged to 170% of nominal capacity, the initial capacity of the electrode could be maintained 2.7 Ah up to 150 cycles without deterioration and a discharge capacity of 1.7 Ah (remaining 63% of 2.7 Ah) could be delivered after 300 cycles. Without overcharge, more than 300 charge-discharge cycles could be realized without loss of capacity and a discharge capacity of electrode could be maintained about 76% of initial capacity …

Electrochemical Behavior Of Imidacloprid, Jie-Qiong Wang, Wang Zhang, Ming Chen, Guo-Wang Diao

Journal of Electrochemistry

The electrochemical behavior of imidacloprid（IDP）on glassy carbon electrode has been investigated by cyclic voltammetry. The result shows that the electrochemical reduction of IDP is irreversible and controlled by diffusion. At 25 ℃, the numbers of the electrons transferred of IDP in the electrochemical reaction are four. The diffusion coefficient of IDP is 2.44×10⁶ cm²·s^-1 and the diffusion activation energy is calculated to be 9.33 kJ·mol^-1.

Dissolved Oxygen Seawater Battery With Electrochemical Capacitance, Hai-Bo Xu, Yong-Hong Lu, Wei Zhang, Yan-Ting Yu, Chuan-Wei Yan, Ya-Ping Sun, Lian Zhong, Jian-Guo Liu, Yi Zheng, Bing Han, Yong-Liang Wang

Journal of Electrochemistry

A new concept of seawater battery with electrochemical capacitance (SWB-EC) has been proposed using carbon fibre brush (CFB) as the cathode material, and three testing prototypes have been made accordingly. The discharge performances of the CFB before- and after-oxidation and Mg alloy sacrifice anode were studied by cyclic voltammetry and constant current discharge tests under steady state conditions. Results show that the oxidized CFB exhibits the pseudo-capacitive characteristic and its activity of oxygen reduction reaction (ORR) in stirred seawater highly increases, comparing with the non-oxidized CFB. The open circuit potential of Mg alloy sacrifice anode is -1.74 V, having the …

Simultaneous Determinations Of Ascorbic Acid, Dopamine And Uric Acid At Ca/Gc Electrode, Ying Zhang, Wang Ren, Min-Jiao Li

Journal of Electrochemistry

The citric acid modified glassy carbon electrode (CA/GC) was constructed by potentiostatic technique and used for simultaneous determinations of ascorbic acid (AA), dopamine (DA) and uric acid (UA) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The CA/GC electrode exhibits excellent electrocatalytic activity towards AA, DA and UA. The oxidation peaks are well separated with the potential differences between AA and DA, DA and UA, and AA and UA being 170, 130 and 300 mV, respectively, which is large enough to determine AA, DA and UA simultaneously. The catalytic peak currents obtained were linearly dependent on the concentrations of …

Progress And Perspective Of Fuel Cell Technology, Ming Hou, Bao-Lian Yi

Journal of Electrochemistry

Fuel cell, a clean and high-efficiency electrochemical power source, has being paid much attention worldwide recent years. In this paper, the progress and perspective of fuel cell technology are elucidated in detail. Fuel cells have been applied in some special fields such as spacecraft, shuttle and submarines. However, in the areas of transportation, stationary station and portable power source, fuel cells are still under demonstration due to the durability and cost problems. The reliability and surrounding survivability of fuel cells should be enhanced in the special application. Meanwhile, the durability and cost of fuel cells are the main issues to …

Preparation And Electrochemical Performance Of Lifepo4/C By Spray Drying Method Assisted With Organic Template, Quan-Bing Liu, Yang-Mei Jiang, Hui-Yu Song, Shi-Jun Liao

Journal of Electrochemistry

In this work, the LiFePO₄/C composites were prepared by the spray drying and carbothermal method, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge measurements. The effects of the organic assisted templates on the morphologies and electrochemical properties of the LiFePO₄/C composites were investigated. The results showed that the morphology and microstructure of the composites could be tuned by incorporating with the different templates. The morphology of the composite appeared to be solid microspheres if no organic template was added, while porous microspheres, nest-like …

Synthesis And Electrochemical Performance Of Xlifepo4·Yli3V2(Po4)3 Composites, Ping-Ping Ma, Zhi-Jian Liu, Jian-Hua Xia, Yu Chen, Pu Hu, Zhi-Chao Lu, Ding-Guo Xia

Journal of Electrochemistry

A series of xLiFePO₄·yLi₃V₂(PO₄)₃ composites were systematically synthesized through solid state reactions by variations in the proportions of LiFePO₄ and Li₃V₂(PO₄)₃. The properties of the prepared compounds were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The capacity of 162.7 mAh/g at 0.2 C rate was obtained with the relatively good cycle stability and good conductivity for 0.95LiFePO₄·0.05Li₃V₂(PO₄)₃ due to more uniformed distributed and smaller particle sizes.

Preparation And Characterization Of Mno/Tin Anode For Lithium Ion Batteries, Gao-Jie Xu, Hai-Yan Yang, Peng-Xian Han, Li-Xue Zhang, Ke-Jun Zhang, Chuan-Jian Zhang, Yu-Hua Fan, Cai-Feng Bi, Guang-Lei Cui

Journal of Electrochemistry

Manganese titanate (MnTiO₃) powder was prepared via a sol-gel method using manganese acetate and tetrabutyl titanate as raw materials, and citric acid as a chelating agent. Through high temperature nitridation of MnTiO₃ powder in ammonia, the MnO/TiN composite was obtained. The phase structure, composition and morphology of the composites were characterized by XRD, SEM and EDS. The electrochemical properties of the composite electrodes were studied by performing cyclic voltammetry, galvanostatic charge and discharge, and electrochemical impedance spectroscopy tests. The MnO/TiN electrode delivered specific capacities of 394 mAh·g^-1 and 146 mAh·g^-1 at the current density of …

Temperature Effects On The Electron-Transfer Reactions Of Fe(Cn)63-/4- And Cytochrome C, Jing Tang, Lin Du, Xiao-Jian Xiao, Ning Zhang

Journal of Electrochemistry

Cyclic voltammetric and chronoamperometric techniques were employed to study the temperature effects on the electrochemical reaction of Fe(CN)₆^3-/4- by self-made thermostatic water bath electrochemical cell. The diffusion coefficient D and the formal heterogeneous electron-transfer rate constant k0 were calculated at different temperatures from 25 °C to 75 °C. In the Fe(CN)₆^3-/4- system, the DO values of Fe(CN)₆^3- were directly proportional to temperature, while DR of Fe(CN)₆^4- inversely proportional to temperature. The values of k^₀ decreased with the increase of temperature due possibly to the electrode passivation resulted from the decomposition of …

Electrochemical Fabrication Of The Ordered Polyaniline Nanowires Array, Yan-Xin Gao, Li-Chao Sun, Su-Yuan Xie, Kang Shi

Journal of Electrochemistry

The effects of electrochemical fabrication methods in different aniline concentrations on the morphologies of polyaniline, which was polymerized on the aligned-multi-walled carbon nanotubes electrode in H₂SO₄ or HClO₄ electrolyte solution, were investigated. It was demonstrated that the polyaniline nanowires would not be prepared by cyclic voltammotry, whereas the nanowires could be obtained by the potentiostatic method without forming the ordered array. Only when the aniline concentration in HClO₄ solution was high enough, the ordered polyaniline nanowires array could be fabricated by the constant current method.

Preparation And Hydrogen Evolution Properties Of Ni/Ag2O/Ruo2-Pt Cathodes, Shu Huang, Xue-Ming Li, Wu-Lin Li, Wen Wang

Journal of Electrochemistry

The Ni/Ag₂O/RuO₂-Pt composite cathode was prepared by sol-gel method using RuCl₃ and H₂PtCl₆ as raw materials. The effects of heat treatment conditions and AgNO₃ concentrations on hydrogen evolution properties were investigated. The morphology and composition of Ni/Ag₂O/RuO₂-Pt composite cathode have been characterized by XRD, XPS and SEM-EDS. It is demonstrated that the surface structure of Ni/Ag₂O/RuO₂-Pt composite cathode is more compact, with fewer cracks and larger surface roughness than pure nickel. At the conditions of 0.3 A·cm^-2, 90 ^oC, and …

Ag Nanoparticles Self-Assembled Films On Iron Surface And Their Inhibition Properties, Zhe Zhang, Ming-Zi Jia, Le Ruan

Journal of Electrochemistry

The Ag nanoparticles were prepared in aqueous solutions through a chemical reduction method and transferred from water phase to toluene phase with the protection of 1-dodecanethiol (DDT). The polished iron electrode was immersed in the DDT-protected metal nanoparticles toluene solutions to form DDT/Ag nanoparticles self-assembled mixed films. Electrochemical methods such as electrochemical impedance spectroscopy and polarization curve measurement were used to study the inhibition properties of the self-assembled films in the 0.5 mol·L^-1 H₂SO₄ solution. The appearance of elements such as S and Ag from the XPS data identified the presences of DDT and Ag nanoparticles.

Function Assignment Within The Haloacid Dehalogenase Superfamily, Hua Huang

Chemistry and Chemical Biology ETDs

The HaloacidDehalogenase Enzyme Superfamily (HADSF) is a ubiquitous family of enzymes. Presently, more than 45,000 deposited gene sequences encode proteins of the HADSF, and only a fraction of these have defined structure and/or function. The work described in this thesis focuses on function determination in several members of the HADSF. An integrated bioinformatic-protein structure-enzyme mechanism approach was used to differentiate and track D-glycero-D-manno-heptose-1,7-bisphosphate phosphatase (GHMB) and histidinol phosphatephosphatase (HisB)orthologues; 2-keto-3-deoxynononic acid 9-phosphatephosphatase (KDN9PP) and 2-keto-3-deoxy-D-manno-octulosonic acid 8-phosphatephosphatase (KDO8PP)orthologues; inorganic pyrophosphatase and β-phosphoglucomutase(β-PGM) orthologues. In addition, a structure-function/bioinformatic analysis was carried-out on the bifunctional 1,3-diposphoglycerate acyltransferase/Cys-S-glyceryl-3-phosphate phosphatase (FKBH). Each study began …

Evolution Of Structure And Function Among Hotdog-Fold Thioesterases And Had Family Phosphatases, Wang Min

Chemistry and Chemical Biology ETDs

My doctoral research began with the function assignment to two domains of fusion protein BT4699, from Bacteriodes thetaiotaomicron, BF1314 from Bacteriodes fragilis and PG1653 from Porphyromonas gingivalis. BT4699, however, is insoluble, so its orthologue BF1314 and PG1653 were prepared and studied. The fusion proteins consist of a domain that belong to a large family of phosphatases known as Haloacid Dehalogenase (HAD) superfamily, and a domain belong to the hotdog-fold thioesterase superfamily. The genes encoding the fusion proteins located at an operon that encoding enzymes involved in the menaquinone biosynthetic pathway. So we assumed that the thioesterase domain is connected to …

Horizontally-Aligned Carbon Nanotubes Arrays And Their Interactions With Liquid Crystal Molecules: Physical Characteristics And Display Applications, Frederick Roussel, Jean-Francois Brun, Alexandre Allart, Limin Huang, Stephen O'Brien

Publications and Research

We report on the physical characteristics of horizonthally-grown Single-Walled Carbon Nanotubes (h-al-SWNT) arrays and their potential use as transparent and conducting alignment layer for liquid crystals display devices. Microscopy (SEM and AFM), spectroscopic (Raman) and electrical investigations demonstrate the strong anisotropy of h-al-SWNT arrays. Optical measurements show that h-al-SWNTs are efficient alignment layers for Liquid Crystal (LC) molecules allowing the fabrication of optical wave plates. Interactions between h-al-SWNT arrays and LC molecules are also investigated evidencing the weak azimuthal anchoring energy at the interface, which, in turn, leads to LC devices with a high pretilt angle. The electro-optical reponses of …

Applications Of Electronic Structure Theory To Problems In Strong-Field Chemistry, Inorganic Chemistry, And Nanomaterial Systems, Jason Anthony Sonk

Wayne State University Dissertations

This dissertation covers research performed on applications of electronic structure theory to various fields of chemistry and is divided into eight chapters. Chapters 2 through 4 describe a series of related works which explore applications of excited state electronic structure methods to problems in strong field chemistry. Chapters 5, 6, and 7 discuss the application of electronic structure theory methods to solving problems in inorganic chemistry. Finally, Chapter 8 looks at an application of electronic structure theory to nanomaterials.

Chapter 2 covers the modeling of electron dynamics of butadiene interacting with a short, intense laser pulse in the absence of …

State-Resolved Slice Imaging Of Photochemical Dynamics, Herath Mudiyans Nuradhika Herath

Wayne State University Dissertations

This dissertation focuses on the understanding the unimolecular photochemistry and dynamics

utilizing state-resolved slice imaging approach combined with the quantum-state selective

spectroscopy technique called resonance enhanced multi photon ionization (REMPI)

method. This powerful technique allows selecting the initial quantum states of the reactants

and determining the nal quantum states, energy, the orientation and alignments of

the products. In the investigations of photodissociation dynamics of acetone at 230 nm,

a bimodal distribution for the resulting CO photoproduct is identied. This observation

indicated the presence of unimolecular dissociation mechanism analogues to the roaming

dynamics reported in formaldehyde photodissociation. Moreover, another type of …

Water Diffusion In And Out Of The Β-Barrel Of Gfp And The Fast Maturing Fluorescent Protein, Turbogfp, Marc Zimmer, Binsen Li, Ramza Shahid, Paola Peshkepija

Chemistry Faculty Publications

The chromophore of fluorescent proteins is formed by an internal cyclization of the tripeptide 65SYG67 fragment and a subsequent oxidation. The oxidation is slow – the kinetics of this step is presumably improved in fast maturing GFPs. Water molecules can aid in the chromophore formation. We have used 50ns molecular dynamics simulations of the mature and immature forms of avGFP and TurboGFP to examine the diffusion of water molecules in-and-out of the protein β-barrel. Most crystal structures of GFPs have well-structured waters within hydrogen-bonding distance of Glu222 and Arg96. It has been proposed that they have an important role in …