Physical Chemistry Commons^™

Localized Corrosion Behavior Of Sensitized 304 Stainless Steel By Scanning Reference Electrode Technique, Chen-Qing Ye, Rong-Gang Hu, Rui-Qing Hou, Xiao-Ping Wang, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Based on a home-built setup of scanning reference electrode technique, and combined with conventional electrochemical measurements, the localized corrosion behavior of sensitized 304 stainless steel (304ss) had been investigated in this work. The results showed that, the non-sensitized 304ss or 304ss sensitized at 550 oC was susceptible to pitting; while 304ss sensitized at 650 oC or 750 oC suffered severe intergranular corrosion in 10% FeCl3 solution.

Application Of Synchrotron Radiation Based Electrochemical In-Situ Techniques To Study Of Electrode Materials For Lithium-Ion Batteries, Zheng-Liang Gong, Wei Zhang, Dong-Ping Lv, Xiao-Gang Hao, Wen Wen, Zheng Jiang, Yong Yang

Journal of Electrochemistry

Due to its merits of high brightness and high intensity, high level of polarization and wide tunability in energy, etc., synchrotron radiation technique provides an unique platform for analysis of the relationship among composition–structure–performance of materials for lithium ion batteries, especially for in-situ, real time dynamic investigation of the electrochemical reaction mechanism, aging process and failure mechanism during charge-discharge cycling. In this paper, we review the latest developments in application of synchrotron based electrochemical in-situ experimental methods to studies of lithium ion batteries. The paper mainly focuses on the application of electrochemical in-siu XRD and XAFS techniques to the investigations …

Controllable Synthesis Of Dispersed Spherical Fe3O4 Nanoparticles As Lithium-Inserted Materials, Hong-Li Zou, Wei-Shan Li

Journal of Electrochemistry

Dispersed spherical Fe₃O₄ nanoparticles were synthesized by a hydrothermal method. The influences of odecyl trimethyl ammonium bromide (DTAB) concentration on the morphology and particle size of the as-prepared Fe₃O₄ were studied. Electrochemical performance of the as-prepared sample as anode materials of lithium ion battery was investigated. It is found that the as-prepared sample exhibits superior rate performance and cycle performance. The nano-sized materials provide structural stability and favor the transfer of lithium ions.

Study On Hydrogen Bubble Template Fabrication Of Porous Biomaterials Coatings By Electrochemically Induced Deposition, Hui Wang, Chang-Jian Lin, Ren Hu, Ke-Qin Zhang, Hong-Ping Duan, Xiang Dong

Journal of Electrochemistry

So far, the pore architecture in biomaterials plays a critical role on the cell response and integration between the biomaterials and implanted environment. In this study, porous calcium phosphate (CaP) coatings and CaP/protein composite coatings have been successfully constructed on titanium substrate by using an electrochemically induced deposition technique. The shape, size and pliability of CaP crystals are controlled by electrolyte concentration, temperature, current density, time and protein additive in preparing process. In addition, the formation mechanism of the porous structure is discussed based on the “hydrogen bubble template” model. It demonstrates that the growth velocity of CaP crystals should …

An Investigation On The Solid Electrolyte Interphase Of Silicon Anode For Li-Ion Batteries Through Force Curve Method, Jie-Yun Zheng, Hao Zheng, Rui Wang, Hong Li, Li-Quan Chen

Journal of Electrochemistry

Non-aqueous electrolyte has been widely used in commercial Li-ion batteries. Optimized choices are proceeding among the various types of salts and solvents in an effort to achieve higher performance of electrolyte. However, the electrolyte will be reduced in low potential and the reductive product will be deposited on the surface of anode to form a passivating layer, solid electrolyte interphase (SEI). Herein an atomic force microscopy (AFM) based method was introduced to study the structure and mechanical property of SEI on silicon thin film anode during the first cycle. Silicon has been known as the most potential candidate anode for …

Preparation And Electrochemical Properties Of Flake-Like Liv3O8 By Soft Template Assisted Sol-Gel Method As Anode Material For Aqueous Li-Ion Battery, Shuai Tan, Dan Sun, Hai-Yan Wang, Tian-Li Hou, Zhong-Xing Xiao, You-Gen Tang

Journal of Electrochemistry

Composite electrode of CuF₂/MoO₃/C was fabricated through high energy mechanical milling. The properties of CuF₂/MoO₃/C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (TEM), galvanostatic charge-discharge measurements, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the grain sizes of CuF₂ and MoO₃ after milling were 200 ~ 300 nm, and the initial discharge capacity of CuF₂/MoO₃/C was 647 mAh·g^-1 at room temperature and at a current density of 10 mAh·g^-1. However, the …

Synthesis And Electrochemical Performance Of Nano Licopo4 By Polyol Method, Fei Wang, Yang Jun

Journal of Electrochemistry

High potential LiCoPO₄ cathode material was synthesized by polyol method. Carbon layer of ca. 3 nm thick was coated on the LiCoPO₄ surfaces by chemical vapor deposition from methylbenzene. Crystalline structure, morphology and electrochemical performance of the sample were studied by XRD, SEM, TEM, CV and galvanostatic charge/discharge curve. The synthesized material via polyol method showed a pure phase of LiCoPO₄. The LiCoPO₄/C electrode delivered a high discharge capacity of 132 mAh·g^-1 and maintained 78% of the initial capacity after 50 cycles at 0.1C rate. The two-step extraction/insertion behavior of Li⁺ in …

Aqueous Solution-Evaporation Route Synthesis And Phase Structural Research Of The Li-Rich Cathode Li1.23Ni0.09Co0.12Mn0.56O2 By In-Situ Xrd, Chong-Heng Shen, Shou-Yu Shen, Zhou Lin, Xiao-Mei Zheng, Hang Su, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

The Li-rich Li_1.23Ni_0.09Co_0.12Mn_0.56O₂ material was synthesized via aqueous solution-evaporation route. The structure and morphology of the material were characterized by means of XRD and SEM. The results indicated that the single particle of the product was polygonal with the size of 330 nm and the structure was layered solid solution with a certain amount of Li₂MnO₃. Electrochemical tests showed that the first discharge capacity of the Li-rich layered material was 250.8 mAh·g^-1 at 0.1C, the capacity retention was 86.5% after 40 cycles. Through in-situ XRD study …

Cmk-3/Sulfur Composite (CXSY) And Room-Temperature Na/S Battery, Qing Zhao, Yu-Xiang Hu, Kai Zhang, Li-Jiang Wang, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

A series of ordered mesoporous carbon (CMK-3)/sulfur composite (C_xS_y) with different sulfur contents were synthesized via a melt-diffusion method. XRD, Raman, BET, SEM, and TEM techniques were used to characterize the structure and morphology of the as-prepared composite. The electrochemical performance of CMK-3/sulfur composite as the electrode of Na/S battery was tested at room temperature. Cyclic voltammograms show that one obvious reduction peak was located at about 1.61V, which is corresponding to the formation of Na₂S_x (x=2~5), while two oxidation peaks were displayed at about 1.82V and 1.95V, which are belonging to the …

Preparation Of The Particle Size Controllable Lifepo4/C And Its Electrochemical Profile Characterization, Ming-E Wang, Jing-Yuan Liu, Meng-Yan Hou, Yong-Yao Xia

Journal of Electrochemistry

We adopted an effective route to prepare the particle size controllable core-shell structure carbon-coated LiFePO₄ from different sized FePO₄ precursors, varying from 80 nm, 200 nm and 1 μm by an in situ polymerization method integrated with a surface modification technology. The discharge capacities of the three sized LiFePO₄/C are, respectively, 162 mAh·g^-1, 142 mAh·g^-1 and 92 mAh·g^-1 at 0.1C rate. The nano-sized LiFePO₄-a/C (80 nm) delivers a discharge capacity as large as 100 mAh·g^-1 even at 30C, while the macroscopic LiFePO₄-c/C (1 μm) exhibits a much …

Surface Composition Structure And Electrochemical Performance Of Aluminum Doped Lifepo4, Huai-Fang Shang, Wei-Feng Huang, Wang-Sheng Hu, Ding-Guo Xia, Zi-Yu Wu

Journal of Electrochemistry

Despite there are many successful reports about the preparation of electrode materials with surface coating for lithium ion batteries, the study in surface self-coating of cathode materials using segregation of doping elements and their electrochemical properties is still very rare. The LiFePO₄ particles with rich-Al on the surface were synthesized by one step solvothermal route. TEM results demonstrated that the surface of the obtained LiFePO₄ particles was well-covered by the amorphous coating. The soft X-ray absorption spectroscopy (XAS) and Auger electron spectroscopy (AES) component analyses revealed that the amorphous coating was composed of LiFe_1-xAl_xPO …

Effect Of Vanadium Substitution On Structure Of Li2Fesio4/C Composites, Yang Hong, Zhang Ying, Cheng Xuan

Journal of Electrochemistry

The carbon coated lithium iron silicate (Li₂FeSiO₄/C) composites were prepared using less expansive iron starting material of soluble ferric nitrate through sol-gel process and solid state reaction. The theoretically calculated amounts of 5, 10, 15, 20, 25, 30, and 50% of vanadium (V) were introduced using NH₄VO₃ to obtain V-substituted Li₂FeSiO₄/C composites. It was found that the pure Li₂FeSiO₄/C composite exhibited a good crystallinity with P2₁/n and nearly no impurities being detected, while the V-substituted Li₂FeSiO₄/C composites showed major …

Preparation And Electrochemical Properties Of Amorphous Znsno3/C By Hydrothermally Carbonization Method, Guo-Qing Fang, Rui-Xue Zhang, Wei-Wei Liu, Bing-Bo Xia, Hong-Dan Sun, Hai-Bo Wang, Jing-Jing Wu, Shinko Kaneko, De-Cheng Li

Journal of Electrochemistry

The amorphous ZnSnO₃@C composite was synthesized via a simple glucose hydrothermal and subsequent carbonization approach. The structure, morphology and electrochemical property of the composite were characterized by XRD, TEM and electrochemical measurements. Compared to bare ZnSnO₃, the ZnSnO₃/C composite exhibited markedly enhanced lithium storage property and cycle performance, delivering a reversible capacity of 659 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1.

Synthesis And Electrochemical Property Of Li2Fesio4/C Cathode Material By Solid State Method, Jiao-Li Sun, Zhi-Jiao Chen, Yi-Xiao Li, Hu Cheng

Journal of Electrochemistry

Li₂FeSiO₄/C cathode material was synthesized using Li₂SiO₃ and FeC₂O₄ as raw materials by solid state method. The structure and morphology of the material were characterized by XRD and SEM. The electrochemical properties of the material were studied by constant-current cyclic testing. The results show that Li₂FeSiO₄/C has a good electrochemical performance. The first discharge capacity of Li₂FeSiO₄/C cathode material at 30oC reached 167 mAh∙g^-1 when cycled at 10 mA∙g^-1 between 1.5 and 4.8 V.

Electrochemical Na-Storage Materials And Their Applications For Na-Ion Batteries, Jiang-Feng Qian, Xue-Ping Gao, Han-Xi Yang

Journal of Electrochemistry

Oncoming large scale electric energy storage (EES) requires battery systems not only to have sufficient storage capacity but also to be cost-effective and environmentally friendly. Li-ion batteries for widespread EES applications may be limited due to the constraint of global lithium resource. From the considerations of available resources and environmental impact, Na-ion batteries have potential advantages as next generation secondary batteries and an alternative to Li-ion batteries. However, in the present state of the art, the Na-storage cathodes reported so far are still deficient both in energy density and power capability, while the carbon and alloy anodes for Na-ion batteries …

High Resolution X-Ray Diffraction Analysis Of Cb1 Receptor Antagonists As A Means To Explore Binding Affinity, Steven P. Fournet

LSU New Orleans Theses and Dissertations

Abstract

Charge density studies have been conducted on ten CB₁ cannabinoid receptor antagonists via high resolution x-ray crystallography. Bond critical point values and various other properties derived from these studies including the electrostatic potential were analyzed in correlation to the affinity of each compound with the CB₁ receptor. Correlation/anti-correlation was found between several properties and K_i. The data was also interpreted by principal component analysis with three principal components accounting for 85% of the data variation. Data mining was limit due to the low sample count and the requirements set for the inclusion of correlated/anti-correlated variables …

Solar Energy Conversion And Control Using Organic Photovoltaic Cells, Kurt Wade Woods

Masters Theses & Specialist Projects

Organic photovoltaic (OPV) cells are advanced, newly emerging technologies that are lightweight, mechanically flexible devices with highthroughput processes from low cost material in a variety of colors. Rathnayake et al. of Western Kentucky University have developed a nanostructure-based OPV cell. Presented in this thesis is a model and simulation of a generalized PV powered system that can predict the performance of solar arrays in various environmental conditions. The simulation has been carried out in Matlab/Simulink, and upon entering the cell’s parameters, it provides key electrical characteristics such as the cell’s I-V curve and efficiency information. The total system that is …

Phosphate Esters, Thiophosphate Esters And Metal Thiophosphates As Lubricant Additives, David W. Johnson, John E. Hils

Chemistry Faculty Publications

Phosphate esters, thiophosphate esters and metal thiophosphates have been used as lubricant additives for over 50 years. While their use has been extensive, a detailed knowledge of how they work has been a much more recent development. In this paper, the use of phosphate esters and thiophosphate esters as anti-wear or extreme pressure additives is reviewed with an emphasis on their mechanism of action. The review includes the use of alkyl phosphates, triaryl phosphates and metal containing thiophosphate esters. The mechanisms of these materials interacting with a range of iron and steel based bearing material are examined.

Morphology And Conformation Of Polythiophene Derivatives In Anisotropic Core-Shell Nanocomposites And Solution, Neil Redeker

Master's Theses

Conjugated semiconducting polymers have garnered substantial interest in recent years due to the potential for use in various applications, particularly in the field of electronic devices such as photovoltaic cells and light emitting diodes. Conjugated polymers offer numerous advantages in these applications, including low cost and high flexibility, but electronic devices based on these materials are currently limited by poor performance. Because of these limitations, increased focus has been placed on improving conjugated polymers for use in commercially viable products. Here, a novel core shell hybrid nanocomposite based on anisotropic zinc oxide nanowires and a side-chain functionalized polythiophene is reported. …

Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi

Graduate Theses and Dissertations

Water-soluble Quantum Dots (QDs) are highly sensitive fluorescent probes that are often used to study biological species. One of the most common ways to render QDs water-soluble for such applications is to apply hydrophilic thiolated ligands to the QD surface. However, these ligands are labile and can be easily exchanged on the QD surface, which can severely limit their application. As one way to overcome this limitation while maintaining a small colloidal size of QDs, we developed a method to stabilize hydrophilic thiolated ligands on the surface of QDs through the formation of a crosslinked shell using a photocrosslinking approach. …

Neutron Study Of Structured Polymers At Interfaces, Thusitha Etampawala

All Dissertations

This work focuses on interfacial structure and dynamics of structured polymers in thin films and in solutions using neutron techniques accompanied by atomic force microscopy. We probed polymers with a common theme that were highly segregated either because of presence of ionic groups or topological constraints. In these polymers the interfacial regions often define their function in different applications such as clean energy, printing adhesions and drug delivery systems. Thin film studies include systems of polystyrene/sulfonated polystyrene, a rigid sulfonated polyphenylene and polystyrene three-arm stars/linear polystyrene. The first two systems include ionic components and the last exhibits topological constraints. Polystyrene …

Synthesis Of Pani/Nihcf Nanocomposite Particles And Eqcm Measurement Of Ion Exchange Properties In Solutions Containing Cd2+, Yu-Jiao Yang, Xiao-Gang Hao, Xu-Li Ma, Zhong-De Wang, Zhong-Lin Zhang, Nian-Chen Han

Journal of Electrochemistry

The PANI/NiHCF nanocomposite particles were synthesized on the CNTs-modified Pt substrate by one-step co-polymerization using cyclic voltammetry. Electrochemical quartz crystal microbalance (EQCM) technique was adopted to investigate the polymerization process of the nanocomposite particles and the mechanism of ion exchange in aqueous solution containing Cd²⁺． The morphology and structure of the as-prepared composite particles were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). Combined with cyclic voltammetry (CV) and energy dispersive spectroscopy (EDS), the electrochemical behavior and the mechanism of ion exchange were also investigated in electrolytes of Cd^{2+ …}

Anaerobic Biotransformation Of Environmental Pollutants Stimulated By Electric Field: Electron-Transfer Mechanisms And Application Examples, Chun-Hua Feng, Dao-Hai Xie, Yun-Meng Pang, Tao Han, Chao-Hai Wei

Journal of Electrochemistry

The ability of some microorganisms to accept electrons from an electrode for the reduction of terminal electron acceptors in anaerobic environments has attracted growing interest on the electric field-stimulated biological reduction technology, which may open new possibility for the sustainable wastewater treatment and bioremediation in the field of environmental engineering. Here, we reviewed the extracellular electron transfer mechanism which is thought to play a key role in determining the feasibility and efficiency for the anaerobic biotransformation of environmental pollutants. Possible mechanisms that may be involved in bioelectrochemical reactors (BERs) with biocathodes include indirect electron transfer via hydrogen generated from water …

Electrochemically Switched Separation Of Yttrium Ion Using Electroactive Nickel Hexacyanoferrate Thin Films In Rare Earth Metal Solution, Hao Zhang, Xiao-Gang Hao, Zhong-De Wang, Zhong-Lin Zhang, Xu-Li Ma, Yi-Bing Li, Shi-Bin Liu

Journal of Electrochemistry

Electroactive nickel hexacyanoferrate (NiHCF) thin films were synthesized by cathodic deposition and investigated as electrochemically switched ion exchange (ESIX) materials for the separation of Y³⁺ from aqueous solutions. In 0.1 mol·L^-1 Y(NO₃)₃ solution, cyclic voltammetry (CV) combined with electrochemical quartz crystal microbalance (EQCM) technique was used to investigate the electroactivity, reversibility of the film electrodes and the mechanism of ion exchange. The electrochemical behavior of NiHCF film electrodes was also compared with that in Sr(NO₃)₂ solutions. The ion selectivity of the film was investigated in 0.1 mol·L^-1 solutions containing [Y(NO_{3 …}

A Comparative Study In Pretreatments Of Acid Chemical Wastewater By Electrochemical Oxidation And Ozonation, Han-Shui Liu, Su Yu, Shao-Ping Tong, Chun-An Ma

Journal of Electrochemistry

Under the condition of keeping certain acidity, the pretreatment efficiency of an acid chemical wastewater (pH 0.85) by electrochemical oxidation was compared with that by ozonation. The results showed that the electrochemical oxidation pretreatment could obtain a better result than the ozonation at pH 0.85. After the addition of 2 g·L^-1 NaCl and with the electrochemical oxidation pretreatment at 30 mA·cm^-2, the removal rate of chemical oxygen demand (CODCr) reached 43.4%, and the value of biochemical oxygen demand/chemical oxygen demand (BOD₅/COD_Cr) also increased from 0.034 to 0.14 in 20 minutes, indicating significantly improvement …

Electrocatalytic Properties Of The Keggin-Type Co(Ii)-Substituted Heteropolyanion Pw11O39Co(Ii)(H2O)5-, Bin Wang, Chong-Tai Wang, Ying-Jie Hua, Jin-Yuan Liu, Liang-Fei Zheng

Journal of Electrochemistry

The electrochemical properties of the Keggin-type Co(II)-substituted heteropolyanion PW₁₁O₃₉Co(II)(H₂O)^5- (PW₁₁Co), as well as the electrocatalytic properties of PW₁₁Co towards the anodic oxidations of H₂O₂ and CH₃OH were studied using the electrochemical methods such as cyclic voltammetry and AC impedance spectroscopy in this paper. An electrocatalytic mechanism of PW₁₁Co as an anodic medium was also proposed. It was found that PW₁₁Co showed a pair of pseudo-reversible redox peaks at the potentials of 1.367 V/1.266 V, corresponding to the redox responses of …

An Investigation Of Photocatalytic Degradation Reactions Of Pollutants By Combination Of (Photo)Electrochemical Measurements, Wen-Hua Leng, Hong-Qiao Zhu

Journal of Electrochemistry

Semiconductor photocatalysis plays a critical role in the environment protection and future energy development. (Photo)electrochemical measurements are powerful tools for studying the kinetics and mechanism of photocatalytic reactions, since photo-carriers, as reactants of photocatalytic reactions, are involved in the interfacial transfer and recombination of semiconductor/electrolyte interface. This review describes the part of our recent results regarding aqueous photocatalytic decontamination obtained by these methods, and the focus of future work in this field is suggested.

Preparation Of Benzoquinone From Phenol By Electrooxidation, Dong-Fang Niu, Cheng-Kai Yu, Xin-Sheng Zhang

Journal of Electrochemistry

The benzoquinone was prepared from phenol by electrooxidation in an H-type cell with cation exchange membrane, in which lead plates were used both as an anode and a cathode, while H₂SO₄ was used as a supporting electrolyte. The effects of current density, concentration of sulphuric acid, concentrations of benzoquinone in electrolyte and extractant on the yields and efficiencies of electrolysis were investigated. Under the optimized conditions of current density being 4 A·dm^-2, concentration of sulphuric acid 1 mol·L^-1, passed charge 3.2 A·h, the yield and current efficiency of benzoquinone could reach 68% and …

Continuous Electroextraction And Concentration Technology, Qiong Ren, Wen Liao, Zu-Cheng Wu

Journal of Electrochemistry

Electrodeionization process combined electrodialysis with ion exchange provides a method to produce pure water and ultrapure water due to the ions accumulated in the resin instantaneously to reduce the system resistance. Meanwhile, large numbers of hydrogen ions and hydroxyl ions are dissociated by water hydrolysis, thus, the ion exchange resins are in-situ regenerated electrochemically. This technology has been utilized to retrieve useful ions which are enriched in the concentrated compartment from a dilute solution. This hybrid process is consequently developed as a new type of extraction and concentration technology and has been gradually employed in the recoveries of heavy metals, …

Experimental Design Methodology Applied To The Oxidation Of Quinolines In Aqueous Medium By Electro-Fenton Process, Souhaila Trabelsi Souissi, Nihal Oturan, Nizar Bellakhal, Mehmet A. Oturan

Journal of Electrochemistry

The degradation behavior of 8-hydroxyquinoleine sulfate (8-HQS), a model molecule of quinolines, was studied in an aqueous medium by electro-Fenton process using a carbon felt cathode and a platinum anode. The great oxidation ability of this process is due to a large production of hydroxyl radical (OH) by electrochemically induced Fenton’s reagent (H₂O₂, Fe²⁺). Hydroxyl radicals are very powerful oxidizing agents which react on organics up to complete mineralization. A factorial experimental design was used for determining the operating parameters on the degradation of 8-HQS in an aqueous medium. The results showed that the …