Materials Chemistry Commons^™

Synthesis And Investigation Of The Liquid Crystalline Properties Of Polycyclic Aromatic Hydrocarbons, Joseph A. Paquette

Theses and Dissertations (Comprehensive)

In this thesis, the synthesis and liquid crystalline properties of a series of novel substituted dibenz[a,c]anthracenes is reported. Specifically, a series of hexaalkoxydibenz[a,c]anthracenes were prepared and found not to exhibit a mesophase. In contrast, when substituents are introduced on the aromatic core, columnar mesophases are observed over broad temperature ranges. A series substituted derivatives was prepared and their mesomorphic properties compared. In general, electron-withdrawing substituents promote broad mesophase temperature ranges, as do larger substituents. The liquid crystalline phase is a result of the electronic effects, size and shape of the substituents in the 10 and 13 positions.

We also synthesized …

The Tetrafluoroborate Salt Of 4-Methoxybenzyl N-2-(Dimethylamino)Ethyl-N-Nitrosocarbamate: Synthesis, Crystal Structure And Dft Calculations, Helene Hedian, Vladimir Benin

Chemistry Faculty Publications

The tetrafluoroborate salt of 4-methoxybenzyl N-2-(dimethylamino)ethyl-N-nitrosocarbamate was prepared in two steps, via the corresponding carbamate. Its crystal structure is monoclinic, space group P21/c. The unit cell dimensions are: a = 19.499(8) Å, b = 5.877(3) Å, c = 15.757(7) Å, α = 90°, β = 110.019(7)°, γ = 90°, V = 1696.5(12) Å3, Z = 4. The structure exhibits an unexpected, pseudo-gauche conformation with respect to the C2–C3 bond, due to a stabilizing hydrogen bond between the carbonyl oxygen (O1) and the hydrogen atom at the trialkylammonium center (H3n), with a distance between them of …

Preparation And Application Of Nano-Nio As Anode In Lithium-Ion Batteries, Cheng-Dong Bai, Jia-Jia Chen, Qi Zhang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

In this work, the nano-NiO material was prepared by hydrothermal method. The surface morphologies and electrochemical properties of nano-NiO material were investigated. The special nano-NiO material with porous surface assembling honeycombs(100-200nm) was obtained by using surface active agents. The discharge capacity of nano-NiO electrode up to 2385.7 mAh/g was achieved at current density of 0.1A/g in the first circle,while 1100mAh/g could be maintained after 100 circles. At current density of 2.0A/g, the discharge capacity of 600 mAh/g was obtained. And when the current density was reduced to 0.1A/g, the discharge capacity was restored to 1050 mAh/g. The nano-NiO electrode exhibited …

Microemulsion Preparation And Electrochemical Characterization Of Pt/C, Ptir/C Electrocatalysts, Ya-Ping Zeng, Sheng Sui

Journal of Electrochemistry

The Pt/C electrocatalysts were prepared by three different systems and the PtIr/C electrocatalysts were prepared with four different Ir contents. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), cyclic voltammetry (CV), potentiostatic and potentiodynamic polarizations measurements. The experimental results confirmed that the electrocatalyst particles prepared by the microemulsion method were well distributed on XC-72R supports with the active particle sizes of 5～10nm and good electrocatalysts activity. The Pt85Ir15/C electrocatalysts showed the highest overall electrochemical activity in unitized regenerative fuel cell.

A Brief Review Of Research Progress In The Development Of Engineering Models For Lithium Ion Batteries, Da-Wei Wang, Dong-Jiang Li, Jun Li, Yong Yang

Journal of Electrochemistry

Lithium ion battery has become an important and popular electrochemical device for energy storage.Suitable evaluation and understanding of electrochemical performance and state of charge play a key role in the applications of lithium ion batteries.Construction and utilization of engineering modeling for lithium ion batteries is an effective way to fulfill this target.In this paper,engineering models of lithium ion batteries based on electrochemical reaction,ionic diffusion and migration are introduced.The emphasis is placed on the development of engineering models by the introduction of side reaction,phase transition,stress and energy.The applications of engineering models in such simulations as charge-discharge,concentration distribution,current distribution,state of charge,stress and …

Superhydrophilic/Superhydrophobic Surface Constructions On Titanium And Their Effects On Anti-Bacterial Properties, Guo-Wei Wang, Qiao-Ling Huang, Ren Hu, Chang-Jian Lin, Hao Wang, Li-Hai Zhang, Pei-Fu Tang

Journal of Electrochemistry

The microbial infection of biomaterials often causes clinic problems and sometimes even leads to the prosthesis failure. It is, therefore, important to prevent the biomaterials from bacterial contamination. This can be done by using anti-bacteria drugs. However, this method causes physiological burdens to the patients and does not always work. To stop the contamination from the just beginning is believed to be a better choice. The first step for infection is the attachment of bacteria on the material. In this work, the thin TiO₂ nanotubes array films were constructed with totally different wettabilities showing either superhydrophobic or superhydrophilic. The …

The Electrochemical Properties Of Cathode Materials LimXV3-XO8, Hui Yang, Gang-Gang Zhao, Juan Li

Journal of Electrochemistry

The cathode material of LiM_xV₃-xO₈ was fabricated by sol-gel method using citric acid as a chelating agent and doping transition metal ions M (Mn, Ti, Co and Ni). The structure, morphology and electrochemical proprieties of the LiMxV3-xO8 samples were investigated by XRD, TGA/DTA, SEM, charge-discharge and CV measurements. The results showed that different calcining temperatures result in different structures and morphologies, which lead to different discharge capacities. The specific discharge capacity of the sample calcined at 500℃ for 6 h was up to 300.4 mAh/g in the first cycle, and the capacity decreased with the …

Electrochemical Properties Of Tungstogermanate And Electrocatalysis Of H2O2 On Gew11Co/P-Opd/Gc Electrode, Li-Li Zhu, Jian-Ying Qu, Jue Wang, Hao-Yue Feng

Journal of Electrochemistry

The electrochemical properties of Co-substituted trimeric tungstogermanate containing Keggin fragments were studied. Cyclic voltammograms revealed two couples of reversible redox peaks on glassy carbon (GC) electrode in acid solutions. They corresponded to two-electron reductions accompanying by the additions of four protons and three protons, respectively, both were controlled by adsorption. The differences in the peak potentials of 2-electron-4-proton and 2-electron-3-proton reactions were 31 mV and 35 mV, respectively..Furthermore, the tungstogermanate (GeW11Co) modified GC electrode with functionalization by poly(o-phenylenediamine) (P-oPD) was prepared readily by electropolymerization. The GeW11Co/P-oPD/GC electrode could electrocatalyze the reduction of hydrogen peroxide, which showed good stability and quick …

Electrochemical Studies On Surface Inclusion Of Β-Cyclodextrin With Adriamycin, Jian Shi, Qi-Ping Zhang, Nan-Ping Wang

Journal of Electrochemistry

The β-cyclodextrin (β-CD) modified gold electrode (β-CD/Au) was fabricated to study the electrochemical behavior of adriamycin (ADM). The results indicated that the complexing reaction of ADM with β-CD took place at the β-CD/Au surface. At 25 °C, the complexing constant (K) was 9.54×10⁴ L·mol^-1 in pH=7.0. The K values changed regularly with temperature, and the most suitable temperature of the surface inclusion reaction was 30 ℃. The complexing reaction of ADM with β-CD at the β-CD/Au surface could undergo the quasi-reversible electrochemical reaction with the rate constant being 0.0995 s^-1. The cathodic peak current (Ip) of …

Preparation And Capacitance Characteristics Of Nickel Oxide Electrode With Mesh-Like Structure, Hui Xu, Zhen-Jun Peng, Dong-Hong Guo, Jun-Ling Li

Journal of Electrochemistry

The mesh-like structure of NiO electrode was obtained by first preparing the precursors via hydrothermal process using nickel sulfate and carbamide as reactants, sodium hexametaphosphate as a surfactant, and followed by calcination of the precursors at 400 ℃. The structure, morphology and capacitance characteristics of NiO electrode were characterized by XRD, SEM and constant current charge-discharge testing techniques. The effects of hydrothermal temperatures on the electrochemical properties of NiO electrode were investigated. The results showed that the better property of nickel oxide was obtained when the mole ratio of nickel to urea was 1:4 and the hydrothermal temperature was 140℃. …

Corrosion Behaviors Of 316 Stainless Steel Weldment Studied By Array Reference Electrodes, Wang-Huo Yang, Rong-Gang Hu, Chen-Qing Ye, Wei Hang, Ning Li, Chang-Jian Lin

Journal of Electrochemistry

The array reference electrodes were developed to in situ measure the potential distributions of the welded 316 stainless steel in 12% FeCl3 solution, combined with metallographic analysis, polarization curve, EIS measurement and Kelvin volta potential imaging. It was indicated that the weld zone of metal suffered a serious preferential corrosion when immersed in the environment due to the distinct changes of structure and composition during the welding process. With time prolonging, the corrosion potential of the welding zone was negatively shifted to a maximum value, and then declined gradually. At 45 min immersion, the corrosion development from welding zone to …

Electroless Plating Silver Without Pd Activation On Polyamide Fabrics And Its Properties, Yun Meng, Ya-Ping Zhao, Zai-Sheng Cai

Journal of Electrochemistry

Silver was deposited on the surface of polyaniline coated polyamide fabrics by electroless plating without using conventional palladium chloride solution as activator．Effects of electroless plating conditions such as the concentrations of silver nitrate, reducing agent glucose, complexing agent ammonium hydroxide, sodium hydroxide in the bath, as well as the depositing time and bath temperature on the rate of metal deposition and the square resistance were studied. Optimum electroless plating conditions were: 30℃, 50 min, with silver nitrate 12 g/L, ammonium hydroxide 100 ml/L, glucose 2.8 g/L, sodium hydroxide 8 g/L. Meanwhile, effects of the intermediate polyaniline layer on the metal …

Electrocatalytic Determination Of 15 Kinds Of Phenolic Compounds By Novel Gold Nanoparticles-Modified Glassy Carbon Electrode, Yan-Ping Cui, Wei-Xing Wang, Chang-Zhu Yang, Wen-Hong Pu

Journal of Electrochemistry

A gold nanoparticles modified glassy carbon electrode (Au/GCE) was used to detect 15 kinds of phenolic compounds. In the cyclic voltammetry measurements, the peak currents of phenolic compounds at Au/GCE were all increased as compared with GCE and planar gold electrodes, and the oxidation potentials were determined by the activity of analytes. Besides, electrocatalysis of salicylic acid was studied at Au/GCE. The results showed that, there was a good linear relationship between the oxidation current and the concentration of salicylic acid, and the current sensitivity was 1.8 fold higher than that obtained on GCE. Trace phenolic compounds determination could be …

Preparation And Characterization Of Casno3 Anode Material For Lithium Ion Batteries, Ran Sun, Zi-Geng Liu, Ya-Qi Jiang

Journal of Electrochemistry

In this study the precursor CaSn(OH)₆ was prepared via a hydrothermal process, and its composition, surface feature and phase-transition were characterized by XRD, SEM and DSC-TGA. The shapes of CaSn(OH)₆ crystals were effectively controlled by adjusting the volumn ratio of H₂O and CH₃CH₂OH solvents. Perovskite CaSnO₃ could be obtained by calcination of CaSn(OH)₆ at 800 ℃. The reversible capacity of 334.4 mAh/g with good cycling stability could be achieved with the CaSnO₃ electrode.

Preparation And Characterization Of The Lani0.6Fe0.4O3-δ Cathode For Intermediate Temperature Solid Oxide Fuel Cell, Hang Liu, Bo Huang, Xin-Jian Zhu

Journal of Electrochemistry

The LaNi_0.6Fe_0.4O_3-δ as cathode material for intermediate temperature solid oxide fuel cell was prepared using a combustion synthesis technique. The X-ray diffraction (XRD) pattern showed that the single-phase LaNi_0.6Fe_0.4O_3-δ perovskite could be obtained after heat treatment at 600°C. The TEM and SEM images of the synthesized powders revealed that the grains were 50-100nm. According to the electrochemical impedance spectra (EIS), the polarization resistance of the symmetric cell LaNi_0.6Fe_0.4O_3-δ/ScSZ/LaNi_0.6Fe_0.4O_3-δ sintered at 1050°C was the smallest (0.70Ω·cm², 0.27Ω·cm^{2 …}

Preparation And Application Of Macroporous Ato/Sio2 Electrode In Electrochemical Degradation Of 4-Chlorophenol, Zhang-Lin Chai, Rui-Feng Zhang, Tong-Hu Xiao, Yun-Xiao Liang

Journal of Electrochemistry

The macroporous ATO/SiO₂ materials were prepared through multiple steps of hydrolysis deposition in ethylene glycol and acetonitrile mixed solutions of SnCl₂/SbCl₃ and subsequent calcination at high temperature. The structures of the obtained materials were characterized by means of SEM and XRD. The results showed that the nano-ATO chemically deposited on the SiO₂ support underwent well-controlled aggregation and recrystallization to form a sandwich structure (ATO-SiO₂-ATO). Through four times loading of ATO the volume resistivity and the specific surface area reached 10·cm and 77 m²·g^-1, respectively. The oxygen evolution potential on …

Dynamic Modeling And Characteristic Analysis Of Proton Exchange Membrane Fuel Cell, Qiu-Hong Jia, Ming Han, Bin Deng, Cai-Zhi Zhang

Journal of Electrochemistry

In this paper, a dynamic model of PEMFC is developed to estimate the dynamic performance of PEMFC by analyzing in detail the influence factors of voltage of PEMFC including various losses. The partial pressure of hydrogen and oxygen is obtained using the differential form of the ideal-gas equation in this model. The steady-state model is obtained by setting reasonable parameter values. The simulation results and experimental results have good consistency, which shows that the simulation model is correct, reasonable and effective. It analyzed the dynamic response characteristics of the output voltage and the partial pressure of hydrogen in condition of …

Indirect Electrochemical Reduction And Cotton Dyeing Process In Fe(Ⅲ)-Oxalate-Calcium Gluconate System, Qing-Zhi Wang, Wei Wang

Journal of Electrochemistry

The electrochemical behavior and possible reaction mechanism in Fe(Ⅲ)-oxalate-calcium gluconate system were studied by cyclic voltammetry. The results showed that Fe(Ⅱ)-gluconate was the final reductant. The reduction time, the working voltage and the cathode area influenced the current efficiency. The high current efficiency of 89% for the indirect electrochemical reduction of Vat Scarlet R could be achieved with reduction time of 10 min, working voltage of 4 V and cathode area of 40 cm² in Fe(Ⅲ)-oxalate-calcium gluconate system.

Electrochemical Behaviors Of Hydroquinone On Polypyrrole/Stab-Nammt/Gc Electrode, Rong Li, Jian Xiong, Wei-Qiong Zhu, Yuan-Yuan Han, Jin Xu, Xiao-Ying He

Journal of Electrochemistry

The PPy/STAB-MMT/GC electrode was made using montmorillonite modified by STAB and polypyrrole (PPy). The electrochemical behaviors of hydroquinone on the PPy/STAB-MMT/GC electrode were researched by cyclic voltammetry and square wave stripping voltammetry (SWSV). The results showed that the electrode reaction occurred on the hydroquinone electrode was controlled by diffusion in PBS (pH=6.0). The number of electron transfer was equal to the number of protons (n=m=1) with the effective area of PPy/STAB-MMT/GC electrode Aeff=0.031 cm². Under the optimized conditions, the linear response of peak current in SWSV with the concentration of hydroquinone in a range of 8.0×10^-6~8.0×10 …

Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne

Articles

A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.

Study On Residual Powders Of Lithium-Ion Batteries With Different Voltages After Explosion, He Li, Zhi-Kui Chen, Ji-Na Cao, Guang-Chuan Liang

Journal of Electrochemistry

The residual powders of lithium-ion batteries at different voltages after explosion were obtained by using the battery impact testing machine. And these powders have been investigated by weighing, water solution and X-ray diffraction (XRD). The results showed that the integrity status of copper current collector and weight of residual powders decreased gradually with increasing of battery voltage, rising of burning temperature and releasing of burning duration time. The residual powders could be separated to insoluble powders and soluble powders by the water solution. The proportion of the insoluble powders is more (about 90%) including C, Co and CoO, while the …

Electrochemical Performance Of Tin Dioxide/Carbon Xerogel Composites As Anode Materials For Lithium-Ion Batteries, Xiao-Jing Liu, Lin-Lin Qin, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The tin dioxide/carbon xerogel composites were synthesized by using vacuum infiltration method. Structural characterization and morphology of the composites were investigated by using XRD, TEM and SEM techniques. BET test was performed to determine the pore size distributions of carbon xerogels and the composites. The results showed that the nano-sized SnO₂ particles (5~10 nm) were encapsulated in the pores of carbon xerogels. During the electrochemical tests the SnO₂ in the composites exhibited capacity retention of 61.9% after 100 cycles of charge-discharge tests at 100 mA/g.

Study On The Fluorescent Carbon Nanodots With Electrochemical Methods, Bao-Ping Qi, Yan-Min Long, Lei Bao, Cui Liu, Zhi-Ling Zhang, Dai-Wen Pang

Journal of Electrochemistry

Carbon nanodots are a new class of fluorescent nanoparticles with a carbon-based core, which possess wavelength-tunable luminescence, high photostability, resistance to photobleaching, water-solubility, and ease of bioconjugation. Owing to their attractive merits, carbon nanodots like other carbon nanomaterials such as fullerene, carbon nanotubes and graphene, have attracted much attention. In addition, carbon nanodots can be inexpensively produced by electrochemical methods with simple post-processing under mild conditions. Electrochemical approaches have unique advantages in the analysis of surface structures and luminescence mechanism of materials. In this review, recent advances in electrochemical methods used for the synthesis and luminescence mechanism of fluorescent carbon …

Effects Of Graphene On Electrochemical Behaviors Of Ni(Oh)2 As Supercapacitor Material, Zhen-Zhen Zhao, Wen-Bin Ni, Neng-Yue Gao, Hong-Bo Wang, Jian-Wei Zhao

Journal of Electrochemistry

The enhanced electrochemical properties of Ni(OH)₂ by the oxidation defected graphene were studied by both experimental method and theoretical calculation. The composite material of nano-Ni(OH)₂/graphene was prepared by potentiostatic deposition on the graphene substrate. Observed by TEM, the Ni(OH)₂ nanoparticles were well dispersed on the graphene substrate with the diameter of 5.0±0.5 nm. The capacitance of the system measured by the electrochemical test was 1928 F·g^-1. As indicated by the theoretical calculations, the composite material becomes conductive since Ni(OH)₂ is combined with surface functional groups of the graphene through the strong chemical interaction. …

Photogenerated Cathodic Protection Of Stainless Steel, Cheng-Gang Lin, Ze-Quan Lin, Jing Li, Chang-Jian Lin

Journal of Electrochemistry

A highly ordered Co-doped TiO₂ nanotube layers were fabricated by potentiostatic anodization of pure titanium in fluorinated electrolyte solutions followed by ion-exchange method. The structure and composition of the as-prepared Co-doped TiO₂ nanotube layers were characterized by SEM, XRD, UV-Vis, and XPS. The effects of dopant content on the morphologies, structural and photochemical properties of the TiO₂ nanotube arrays were investigated. The performances of photogenerated cathodic protection and the photoelectrochemical response for the Co-doped TiO₂ nanotube arrays under illumination and dark conditions were evaluated through the electrochemical measurements. The Co-doped TiO₂ nanotubes showed a stronger …

Electrelectrochemical Performances Of C-Coating And Co-Doping Lifepo4, Ying Bai, Jue-Ming Yang, Chun-Bo Qing, Wei-Feng Zhang

Journal of Electrochemistry

Phospho-olivine LiFePO₄ cathode materials were prepared by hydrothermal reaction at 200 ^oC. Sucrose was added as C-coating resource and Co was doped into the crystal lattice of LiFePO₄. In order to investigate the improvements in the electrochemical properties of Co-doped LiFePO₄, three samples, LiFePO₄, C-coated LiFePO₄ and C-coating-Co-doped LiFePO₄, were synthesized under the same preparation conditions. Charge/discharge studies reveal that the Co-doped LiFePO₄/C composite annealed at 400 ^oC exhibits marked improvement of specific capacity by diminishing the particle sizes and enhancement in the degree of crystallinity. …

Simultaneous Determination Of Dopamine(Da)And Epinephrine (Ep) At Ca/Gc Electrode, Wang Ren, Ying Zhang, Min-Jiao Li

Journal of Electrochemistry

The citric acid modified glassy carbon electrode (CA/GC) was prepared by potentiostatic technique and was used for detections of dopamine (DA), epinephrine (EP), and their mixtures by differential pulse voltammetry (DPV). The modified electrode shows the enhanced sensitivity and excellent electrochemical discrimination to DA and EP. The cathodic potential difference between DA and EP was about 380 mV, while no cathodic reduction of ascorbic acid (AA) was observed because the oxidation of AA is an irreversible reaction at the sensor. As a result, DA and EP could be determined simultaneously with the interferences of high concentrations of AA being eliminated. …

Development Of Dehydrogenase-Based Bioanode Using Poly(Phenosafranin)-Functionalized Swcnt Nanocomposites And Its Application To Ethanol Biosensor, S. Saleh Farhana, Okajima Takeyoshi, Lanqun Mao, Takeo Ohsaka

Journal of Electrochemistry

A New type of dehydrogenase-based amperometric ethanol biosensor was constructed using alcohol dehydrogenase (ADH) which was immobilized on the edge-plane pyrolytic graphite (EPPG) electrode modified with poly(phenosafranin)-functionalized single-walled carbon nanotube (PPS-SWCNT). The PPS-SWCNT modified EPPG electrode was prepared by electropolymerization of phenosafranin on the EPPG electrode which was previously coated with SWCNT. The performance of the ADH/PPS-SWCNT/EPPG electrode was evaluated using cyclic voltammetry and amperometry in the presence of ethanol. The fabricated ethanol biosensor provided a reasonable sensitivity of 2.0 μA cm–2 mM–1 and a low detection limit (36 μM) for the electrocatalytic oxidation of ethanol with a linear concentration …

Electrochemical Analysis Based On Molecular Recognition Of Nucleic Acids And Its Applications, Dian-Ming Zhou, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu

Journal of Electrochemistry

Nucleic acid as the carrier of genetic information and the functional molecules for molecular biology and bioanalytical chemistry has attracted increasing interest in electrochemical analysis. This review presents a brief outline of some electrochemical analytical assays based on molecular recognition of nucleic acids. Most of these methods are focused on the detection of nucleic acid sequence, genetic mutation and nucleic acids as functional molecules.

Fabrication Of Ito Micro-Pore Electrochemical Sensor And The Detection Of Exocytosis, Hui Zhao, Ling Li, Pin-Gang He, Yu-Zhi Fang

Journal of Electrochemistry

Exocytosis is one of the major means for cells to transmit messages. Amperometric detection of exocytosis is an important method in studying communication between cells. In this study a new type of ITO micro-pore electrochemical sensor was fabricated by means of ITO and UV light lithographic mask and was used in the detection of exocytosis with promising results. Compared with the conventional method, the ITO micro-pore sensor can not only replace the carbon fiber electrode, but be combined with fluorescent or chemiluminescent methods in detecting the physiological phenomena of cells.