Materials 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.

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 …

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 …

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 …

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.

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 …

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 …

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.

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 …

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 a …

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 mAhg^-1 when cycled at 10 mAg^-1 between 1.5 and 4.8 V.

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

Anode material has become the key issue for restricting the development of aqueous lithium ion battery (ALIB). Flake-like LiV3O8 materials were synthesized by sol-gel method using sodium dodecyl benzene sulfonate (SDBS) as a template. The XRD and SEM results showed that as-prepared flake-like LiV₃O₈ was of high purity with monoclinic system and P21/m space group. LiMn₂O₄//Li₂SO₄//LiV₃O₈ ALIB was assembled and tested. As observed, the flake-like LiV3O8 here exhibited good high-rate performance and cycling stability. A high discharge capacity of 154 mAh.g^-1 (based on the mass …

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 LiCoPO4/C …

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 poorer discharge …

High Yield Solvothermal Synthesis Of Hexaniobate Based Nanocomposites Via The Capture Of Preformed Nanoparticles In Scrolled Nanosheets, Shivaprasad Reddy Adireddy

University of New Orleans Theses and Dissertations

The ability to encapsulate linear nanoparticle (NP) chains in scrolled nanosheets is an important advance in the formation of nanocomposites.These nanopeapods (NPPs) exhibit interesting properties that may not be achieved by individual entities. Consequently, to fully exploit the potential of NPPs, the fabrication of NPPs must focus on producing composites with unique combinations of morphologically uniform nanomaterials. Various methods can produce NPPs, but expanding these methods to a wide variety of material combinations can be difficult. Recent work in our group has resulted in the in situ formation of peapod-like structures based on chains of cobalt NPs. Building on this …

Nmr Determination Of Enantiomeric Composition Of Chiral Alcohols Using Camphorsulfonate Esters, Steven Bondi Fcrh '11, Thomas Lobasso Fcrh '09, Christa Iwanoski Fcrh '09, Shahrokh Saba, Donald Clarke

The Fordham Undergraduate Research Journal

Most biologically active compounds, including pharmaceuticals, have chiral molecular structures. With increased recognition that enantiomers of chiral drugs are metabolized differently, there has been enormous interest in the development of enantioselective methodologies for the synthesis of chiral compounds. NMR spectroscopy has emerged as a powerful method for discrimination of enantiomers of chiral compounds. 1 One strategy by which the NMR method is exploited is based on converting the enantiomers of a chiral compound to diastereomers using a chiral derivatizing agent. These diastereomers often display anisochronous NMR signals, which can be identified and integrated affording quantitative measurements of the optical purity …

Biogenic Synthesis, Photocatalytic, And Photoelectrochemical Performance Of Ag–Zno Nanocomposite, S. A. Ansari, Mohammad Mansoob Khan Dr, M. O. Ansari, J. Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

The development of coupled photoactive materials (metal/semiconductor) has resulted in significant advancements in heterogeneous visible light photocatalysis. This work reports the novel biogenic synthesis of visible light active Ag–ZnO nanocomposite for photocatalysis and photoelectrode using an electrochemically active biofilm (EAB). The results showed that the EAB functioned as a biogenic reducing tool for the reduction of Ag+, thereby eliminating the need for conventional reducing agents. The as-prepared Ag–ZnO nanocomposite was characterized by X-ray diffraction, transmission electron microscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic experiments showed that the Ag–ZnO nanocomposite possessed excellent visible light photocatalytic activity …

Third-Order Nonlinear Optical Properties Of Chemically Synthesized Copper Oxide Nanosheets, Mahdi Shahmiri

mahdi shahmiri

Copper oxide (CuO) nanosheets were obtained by a quick-precipitation method using Cu(NO3)2 and NaOH in the presence of polyvinylpyrrolidone (PVP). Different sizes of CuO nanosheets were achieved by varying the PVP concentration. The crystal structure, morphology, and optical properties of the CuO nanosheets were characterized by X-ray diffraction, transmission electron microscopy, and diffuse reflectance spectroscopy. Higher PVP concentrations produced CuO nanosheets with enhanced crystalline structure, reduced particle size, and enlarged band gap. Nonlinear optical characteristics were examined by the Z-scan technique using a blue continuous wave laser beam operated at 405 nm. Increased PVP concentration from 0.5 wt% to 5 …

Hydrogen Evolution Reaction Measurements Of Dealloyed Porous Nicu, Kyla Koboski, Evan Nelsen, Jennifer R. Hampton

Faculty Publications

Porous metals are of interest for their high surface area and potential for enhanced catalytic behavior. Electrodeposited NiCu thin films with a range of compositions were electrochemically dealloyed to selectively remove the Cu component. The film structure, composition, and reactivity of these samples were characterized both before and after the dealloying step using scanning electron microscopy, energy-dispersive spectroscopy, and electrochemical measurements. The catalytic behavior of the dealloyed porous Ni samples towards the hydrogen evolution reaction was measured and compared to that of the as-deposited samples. The dealloyed samples were generally more reactive than their as-deposited counterparts at low overpotentials, making …

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.

Quantum Dot Enhanced Epitaxial Lift-Off Solar Cells, Mitchell F. Bennett

Theses

Embedded nanostructures such as quantum dots (QDs) have been studied for many applications in solar cells including enhanced mini-band absorption in intermediate-band solar cells and current matching in multi junction cells. The major drawbacks of using such techniques to decrease intrinsic solar cell loss mechanisms are twofold: first, it is difficult to maintain partially populated states using QDs due to a quick thermal extraction of carriers; second, QDs have a weak absorption which necessitates a near-perfect control of QD growth mechanisms to carefully ensure a balance between dot size and density. One avenue for improving absorption into QDs is to …

Interactive Wireless Sensor For Remote Trace Detection And Recognition Of Hazardous Gases, Audrey Lama

Masters Theses & Specialist Projects

The interactive wireless sensor detects many hazardous gases such as Hexane, Propane, Carbon monoxide and Hydrogen. These gases are highly toxic and used in different kinds of manufacturing industries, domestic purpose and so on. So, building a sensor that can detect this kind of gases can save the environment; prevent the potential for explosion, and endangering human life. In long term, interactive wireless sensor can also prevent the financial losses that might occur due to the hazardous incident that might occur due to these toxic gases.

Hexane is a colorless, strong gas which inhaled in significant amounts by a person …

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. …

Synthesis And Structures Of New Three-Dimensional Copper Metal-Organic Frameworks, Nitin Kumar Pally

Masters Theses & Specialist Projects

Metal-organic frameworks (MOFs) are crystalline materials with metal ions covalently bonded to organic ligands. The ligands act as spacers often creating a porous structure with very high pore volume and surface area. MOFs are known for their robust structures, high porosity, and different chemical functionalities and are considered for applications in adsorptions, separations, catalysis and gas storage. This work focuses on the synthesis of new MOFs using copper compounds. Different types of carboxylate ligands were used for the synthesis. Two new copper-organic frameworks, [Cu₃(pyz)(btc)] (1), and [(Cu₃(btc))•xH₂O] (2) (btc= benzene-1,3,5-tricarboxylate, pyz= pyrazine) have been …

Characterization Of The Corrosion And Oxide Film Properties Of Alloy 600 And Alloy 800, Melissa Faichuk

Electronic Thesis and Dissertation Repository

The passive film properties of Alloy 600 and Alloy 800, both of which are used as steam generator tubing in CANDU reactors, have been studied using techniques such as polarization scans, electrochemical impedance spectroscopy and X-ray photoelectron and Auger spectroscopies. The composition of the oxides formed in a 0.1 M Na₂S₂O₃ solution have been characterized over a wide range of potentials from the pre-passive, through the passive to the transpassive regions. These changes have been correlated to the electrochemical behaviour. A second set of experiments was performed to determine the effectiveness of the surface mechanical …

Poly (N-Isopropylacrylamide) Microgel-Based Etalons And Etalon Arrays For Determining The Molecular Weight Of Polymers In Solution, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Positively and/or negatively charged poly (N-isopropylacrylamide)-based microgels were deposited on a single substrate and isolated regions of Au overlayers were deposited on top of the microgels. Each spatially isolated Au overlayer region had a different thickness to make an etalon array.We found that areas with a thin Au overlayer (5 nm) responded to a range of polymer molecular weights (MW), while areas with a thick overlayer (35 nm) can only respond to low molecular weight polyelectrolytes. By comparing the optical responses of the device’s individual array elements, a good approximation of the polyelectrolyteMWin solution can be made.

Development Of Biodegradable And Stimuli-Responsive Macromolescules And Their Assemblies, Ali Nazemi

Electronic Thesis and Dissertation Repository

Polymersomes are potentially multifunctional soft materials constructed by the self-assembly of amphiphilic block copolymers in aqueous medium. While much research has focused on controlling the assembly and encapsulation properties of polymersomes, their surface functionalization has been relatively unexplored. This is important because it plays a critical role in determining their properties such as toxicity and biodistribution behavior. The work described in this thesis involves the development of a biocompatible and biodegradable polymersome systems based on poly(ethylene oxide)-b-polycaprolactone (PEO-PCL) block copolymers with azide surface groups as a novel scaffold for various biomedical applications. The surface functionalization of these polymersomes …

An Investigation Of Thin Films Formed On Zinc By Spectroscopic Ellipsometry, Juan Zuo, Ying Chen, Chang-Jian Lin, Andreas Erbe

Journal of Electrochemistry

The formation of natural oxide films on polycrystalline zinc surface, the growth of natural oxide films in different atmospheres, as well as the electrochemical process of metal zinc in alkaline carbonate solution, studied recently by using spectroscopic ellipsometry in our group, are introduced. The objective of this paper is to outline that the optical, electrical properties, the change and growth kinetics of zinc metal oxide film on the surface can be investigated by in-situ and ex-situ ellipsometry, which makes significant sense to evaluate the overall performance of zinc oxide layer.

Corrosion Behavior Of Zinc Covered With Thin Electrolyte Layers Under External Electric Field, Xu-Jie Yuan, Jun-Xi Zhang, Shi-Ming Zhang, Tian Tan, Qi-Meng Chen

Journal of Electrochemistry

The corrosion behavior of zinc covered with thin electrolyte layers (TELs) under an application of external electric field was investigated by performing corrosion potential and cathodic polarization current measurements. The results showed that the Ecorr and ic values first increased and then decreased with the increase of electrolyte layer thickness. Pure zinc exhibited the maximum corrosion potential as the TELs increased to 400 μm under the controls of cathodic process and corrosion products. The application of external electric field resulted in either a negative shift in corrosion potential of zinc or an increase of cathodic current. The effect of external …

Corrosion Behavior Of A High Strength Low Alloy Steel Under Hydrostatic Pressure In Deep Ocean, Hai-Jing Sun, Li Liu, Ying Li

Journal of Electrochemistry

The corrosion behavior of a high strength low alloy steel (HSLA steel) in 3.5% NaCl solution under hydrostatic pressure (HP) in deep ocean has been investigated by performing weight loss measurement, obtaining potentiodynamic polarization curve and emplying electrochemical impedance spectroscopy (EIS) using the set up for simulation of deep sea environment in laboratory. The results were compared with that at atmospheric pressure and the influence of HP was emphatically discussed. The results revealed identical corrosion mechanism for HSLA steel at 3.5 × 106 Pa and 1 × 105 Pa. Howevere, the development of such a corrosion process was remarkably accelerated …