Chemistry Commons^™

Electrochemical Determination Of Hg(Ii) At Gold Nanoparticles@Carbonaceous Microspheres Modified Electrode, Tian-Yu Qiu, Ming-Chun Wang, Xian-Feng Du, Tian-Jia Jiang, Xing-Jiu Huang

Journal of Electrochemistry

The gold nanoparticles@carbonaceous microspheres (Au@CMSs) and  Au@CMSs modified glassy carbon electrode (GCE) were prepared. The Au@CMSs modified  GCE was further examined for possible sensitive detection of mercury ions (Hg(II)) in an aqueous solution by square wave anodic stripping voltammetry (SWASV). The excellent performance was found in the stripping analysis of Hg(II) in 0.1 mol•L^-1 NaAc-HAc(pH=5.0) with a sensitivity of 25.863 A•(mol•L^-1)^-1 and a detection limit of 3.69×10^-8 mol•L^-1 based on the 3σ method.

Fabrication Of Riboflavin Electrochemical Sensor Based On Au Nanoparticles/Polydopamine/Carbon Nanotubes Modified Glassy Carbon Electrode, Hua-Ping Peng, Mei-Ling Yu, Xin Liu, Pan Liu, Wei Chen, Ai-Lin Liu, Xin-Hua Lin

Journal of Electrochemistry

A novel electrochemical platform for the high sensitivity detection of riboflavin was constructed by Au nanoparticles/polydopamine/carbon nanotubes (Au-PDA-MWCNTs) nanocomposite modified glassy carbon electrode. The Au-PDA-MWCNTs nanocomposite was synthesized by in situ reduction method. The characteristics of the as-prepared Au-PDA-MWCNTs nanocomposite modified electrodes were investigated by using UV-Vis spectroscopy, scanning electron microscopy (SEM) and electrochemical methods. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrochemical behavior of riboflavin (RF) at Au-PDA-MWCNTs nanocomposite modified electrodes. The results demonstrated that the present electrochemical sensor exhibited a wide linear range from 5×10^-9 mol•L^-1to 1×10^-5 mol•L …

The Study On Comparison Of Electrochemical Performance In Microbial Fuel Cell With Glucose And Sodium Acetate Acting As Substrates, Lei Fan, Yu Zhao, Ting Li, Qin-Bo Yuan, En-Zhi Wang, Xiao-Bin Wang, Jun-Wen Wang

Journal of Electrochemistry

By inoculating aerobic sludge and anaerobic sludge from the sewage treatment plant, two sets of dual-chamber microbial fuel cells (MFCs) were built with either glucose or sodium acetate acting as a substrate. Accordingly, the electrochemical performances of MFCs were explored with the concentration of the substrates being 0.0335 mol⋅L^-1. The results of the comparative study in glucose system and sodium acetate system showed that the impedance values of anodic half cell were 222 Ω for glucose and 213.67 Ω for sodium acetate, implying no significant effect on the internal resistance in battery with the different substrates. The exchange …

The Dawn Of New Quantum Dots: Synthesis And Characterization Of Ge1-Xsnx Nanocrystals For Tunable Bandgaps., Richard J. Esteves

Theses and Dissertations

Ge_1-xSn_x alloys are among a small class of benign semiconductors with composition tunable bandgaps in the near-infrared spectrum. As the amount of Sn is increased the band energy decreases and a transition from indirect to direct band structure occurs. Hence, they are prime candidates for fabrication of Si-compatible electronic and photonic devices, field effect transistors, and novel charge storage device applications. Success has been achieved with the growth of Ge_1-xSn_x thin film alloys with Sn compositions up to 34%. However, the synthesis of nanocrystalline alloys has proven difficult due to larger discrepancies (~14%) in …

Special Issue: Electrochemistry Of Carbon Materials, Wei Chen

Journal of Electrochemistry

Carbon materials are traditional electrode materials due to their excellent electrical conductivities, high electrochemical stabilities and wide potential windows. Glassy carbon, graphite, various activated charcoals, carbon fibers etc. have been widely used in electrochemistry serving as electrode substrates or supports. In addition to their applications in basic electrochemistry, carbon materials have also played important roles in electrochemical energy storage and conversion. In recent years, various types of carbon structures, from zero-dimensional carbon nanodots, one-dimensional nanotubes, two-dimensional graphene to three-dimensional porous carbons, have attracted increasing attention in electrochemical field. It has been found that carbon materials have outstanding properties as advanced …

Applications Of Carbon Materials In Electrochemical Energy Storage, Ji Liang, Lei Wen, Hui-Ming Cheng, Feng Li

Journal of Electrochemistry

An electrode material for electrochemical energy storage is one of the key components for high performance devices. In a variety of electrochemical energy storage systems, carbon materials, especially the lately emerged carbon nanomaterials including the carbon nanotube and graphene, have been playing a very important role and brought new vitality to the development and demonstration of the broad application prospects. In this review, we summarize the applications of various carbon materials in the typical electrochemical energy storage devices, namely lithium/sodium ion batteries, supercapacitors, and lithium-sulfur batteries, as well as flexible electrochemical energy storage and electrochemical catalysis. A perspective of novel …

Progress Of Self-Supported Supercapacitor Electrode Materials Based On Carbon Substrates, Shui-Jian He, Wei Chen

Journal of Electrochemistry

Self-supported electrode materials have been widely used in supercapacitors. Carbon materials are promising substrates in building self-supported electrode materials attributed to their diverse structures, rich resource, relatively low cost and high stability. Combined with our own research in this field, we summarize here the recent progress on the synthesis of self-supported electrode materials and their supercapacitance properties. The overall synthetic strategy could be divided into two categories: “top-down” and “bottom-up”. We hope this review is helpful for the development and application of renewable sources in self-supported electrode materials.

Colloidal Ionic Supercapacitors, Kun-Feng Chen, Dong-Feng Xue

Journal of Electrochemistry

Supercapacitors have high power density and long cycle life compared with battery systems, but they still suffer from low energy density at the same time. In order to increase the energy density of supercapacitors, we have developed a new type of pseudocapacitor, called colloidal ion supercapacitor, which can directly use commercial metal salts as electrode materials and form electroactive matter by in-situ electrochemical reactions without the need of additional materials synthesis processes. Colloidal ion supercapacitor can fully utilize the redox reaction of metal cations with multiple oxidation states, which can completely release the stored electrical energy of multiple-valence cations, leading …

Synthesis Of Porous Carbon Nanosheets And Its Application In Sodium-Ion Battery, Jing-Fei Zhang, Jing Lu, Xiao-Yu Yang, Yun-Di Huang, Lin Xu, Dong-Mei Sun, Ya-Wen Tang

Journal of Electrochemistry

Owning to sodium’s high abundance, relatively low cost, similar chemical properties to Li and very suitable redox potential of E₀(Na⁺/Na) = -2.71 V versus SHE which is only 0.3 V above that of lithium, rechargeable sodium ion battery hold much promise as potential alternatives to current lithium ion batteries for energy storage applications. Carbon material is regarded as the most promising anode candidate for sodium ion battery. Particularly, carbon nanosheet with porous structure and high conductivity is expected to have improved sodium ion storage properties. In this paper, we present a two-step pyrolysis-based method for facile …

Carbon Aerogel/Nickel Foam As Electrode For High-Performance Supercapacitor, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

Herein, a facile synthesis has been explored to prepare carbon aerogel/Ni foam. Graphene oxide, resorcinol and formaldehyde serve as precursors and polymerize in-situ on the Ni foam after hydrothermal synthesis at 85 ℃. After lyophilization treatment, the carbon aerogel/Ni foam with porous structure can be obtained. Electrochemical investigations reveal that the carbon aerogel/Ni foam exhibits superior performances in both aqueous and organic electrolytes involving high specific capacitance and long-term cycling stability. The excellent properties can be ascribed to the unique formation and porous structure, which allows more effective transportations of electron and electrolyte ion.

Effect Of Mno2 Content On Electrochemical Capacitance Behavior Of Active Carbon Electrode, Kun Shen, Xian-Liang Zhou, Qi-Shun Duan

Journal of Electrochemistry

In this work, the manganese dioxide (MnO₂) materials were prepared by solution approach at low temperature, thermal decomposition and electrochemical deposition. The actived carbon (AC) and MnO₂composite electrodes were used for aqueous supercapacitors. The morphologies and structures of the prepared materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the electrochemical behaviors were tested by cyclic voltammetry (CV) and galanostatic charge-discharge tests. Electrochemical test data show that the maximum specific capacitances of 151, 172 and 141 F•g^-1were obtained with the contents of MnO₂being 70, 60 and 70% in …

Real-Time Supervised Detection Of Pink Areas In Dermoscopic Images Of Melanoma: Importance Of Color Shades, Texture And Location, Ravneet Kaur, P. P. Albano, Justin G. Cole, Jason R. Hagerty, Robert W. Leander, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

Background/Purpose: Early detection of malignant melanoma is an important public health challenge. In the USA, dermatologists are seeing more melanomas at an early stage, before classic melanoma features have become apparent. Pink color is a feature of these early melanomas. If rapid and accurate automatic detection of pink color in these melanomas could be accomplished, there could be significant public health benefits.

Methods: Detection of three shades of pink (light pink, dark pink, and orange pink) was accomplished using color analysis techniques in five color planes (red, green, blue, hue, and saturation). Color shade analysis was performed using a logistic …

Sulfonated-Graphene/Nafion Composite Membrane For All Vanadium Redox Flow Batteries, Da-Wei Yang, Yan-Qing Dong, Jing-Min Fan, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Nafion membrane has been widely used in fuel cells due to its good proton conductivity, chemical and mechanical stabilities. However, the well-developed water channels in Nafion membrane have restricted its application in all vanadium redox flow batteries owing to the high permeation of vanadium ions and the cost. In this work, the water adsorption rate, resistivity and transference number of vanadium ions of sulfonated-graphene/Nafion composite membrane were investigated and compared with those of Nafion membrane in an effort to overcome the abovementioned drawbacks. It was found that the area resistivity and permeation rate of sulfonated-graphene/Nafion composite membrane were significantly reduced …

Research Progress Of Secondary Sodium-Air Batteries, San-Pei Zhang, Zhao-Yin Wen, Jun Jin, Xiang-Wei Wu, Ying-Ying Hu, Mei-Fen Wu

Journal of Electrochemistry

Rechargeable sodium-air batteries have been the focus in the fields of batteries and energy storage recently, owing to their high specific energy density (1600 Wh·kg^-1), an equilibrium discharge potential of 2.3 V and earth-abundant sodium element However, research on sodium-air cells is still in an infant age and presents many scientific issues. Based on recently reported work and our own experience on sodium-based batteries, this review summarizes the research progress related to the critical scientific is sues of secondary sodium-air batteries and the application prospect of sodium-air battery.

Preparations And Properties Of Polybenzimidazole/Polyvinylbenzyl Crosslinked Composite Membranes For High Temperature Proton Exchange Membrane Fuel Cells, Jin-Kai Hao, Yong-Yi Jiang, Zhen Wang, Xiao-Jin Li, Zhi-Gang Shao, Bao-Lian Yi

Journal of Electrochemistry

In order to increase the chemical stability of polybenzimidazole (PBl) membrane, a highly stable polymer, poly vinyl. benzyl chloride (PVBC), was chosen as the macromolecular crosslinker, and 1H-1,2,4-triazol was adopted to prepare the crosslinked PBI-based membranes. The influence of the PVBC amount on membrane characteristic was investigated in detail. The results indi. cated that the crosslinked structure of the membrane effectively improved the chemical stability, and at the same time, the mem. brane presented good mechanical property and proton conductivity. The fuel cell performance for the membrane was tested with hy. drogen and oxygen single cell without humidification at 150 …

Development Of Proton Conduction Membranes In Application Of Vanadium Flow Battery, Le-Tu Qingge, Wei-Nan Guo, Ping Liu, Bao-Guo Wang

Journal of Electrochemistry

The polymeric hydrophilic/hydrophobic interactions into membrane formation were introduced. A general and straightforward strategy for preparing membranes with nanometer-scale pores was suggested by utilization of hydrophilic/hydrophobic interactions to generate phase separation and removal of polyion aggregates through water immersion. Poly(vinylidene fluoride) (PVDF) and sodium allyl sulfonate (SAS) serve as the membrane material and pore-generator, respectively, resulting in chemically stable and oxidation-resistant membranes with various potential applications. Following the same procedure invented to produce the laboratory-scale membranes, the scale-up process to manufacture large-area membranes was completed. The obtained membrane exhibited the conductivity of 3.5×10^-2 S•cm^-1, thickness of 100 …

Review For Applications Of "Lead Carbon" Batteries In Energy Storage System, Yong-Quan Ma, Ke Ke, Da-Ming Gu

Journal of Electrochemistry

Three types of “lead carbon” batteries are introduced by comparing their advantages and disadvantages. Then their applications in energy storage system (ESS), especially in the field of renewable energy power generation, are discussed. The prospects and potential applications of “lead carbon” batteries in EES for electric power supply system are analyzed by combining the state-of-the-art techniques in this field.

Characterization Of The Separator With Thermal-Shutdown Layer For Use In Lithium Batteries, Li Bai, Yong-Jian Huai, Xin-Ping Ai, Hai Jia

Journal of Electrochemistry

In this paper, the lithium ion battery coated with the thermal-shutdown functional layer has been introduced. The shutdown temperature of the separator could be decreased by using the melting point of thermal-shutdown functional layer. When the internal battery environment reached a critical temperature, the functional layer melted and coated the anode/separator with a non-conductive barrier, halting Li-ion transport and shutting down the cell permanently. The results showed that the functional layer did not affect the resistance, rate performance and cycle life. It was found the functional layer can significantly improve the safety of the battery when misused.

Impact Of Water Content On The Performance Of Lifepo4 Based Lithium-Ion Battery, Jun-Ting Niu, Lin Sun, Shu-Wen Kang, Zhen-Wei Zhao, Zi-Feng Ma

Journal of Electrochemistry

Through different dry conditions and measuring by moisture test instrument, cathode pole pieces with different water contents of 0.3‰ ~ 0.7‰ were obtained to prepare lithium-ion batteries. Cycling performance and high rate performance at 1C ~ 5C discharge rates were tested. Moreover, ASR performances of LiFePO4 base lithium-ion batteries after 200 cycles with different water contents were investigated by EIS. The results showed that the cycle performance and rate performance were closely related to the water content of the electrode. When the water content went up to 0.6‰ the cycle stability and rate performance fell. Meanwhile, the internal resistance and …

Effects Of Microstructures Of Active Material On Performance Of Vrla Battery, Lei Jiang, Shou-Zhong Yi

Journal of Electrochemistry

The structure, morphology and content of the as-prepared and the processed samples were characterized by the means of SEM and XRD. The discharge capacities and cycle life performances of the as-prepared and the processed samples were tested by electrochemical measurements with different rates. The results indicated that the 4BS technology which can affect the plate design, deep cycle capability and cycle life is a basic technology for the VRLA batteries. It was also confirmed that the contents and structures of α-PbO₂ and β-PbO₂ formed with different processing conditions can affect the performance of the VRLA batteries, suggesting that …

Preparation And Performance Of Lithium-Rich Manganese Layered Materialsâ 0.6li[Li1/3Mn2/3]O2·0.4liniXMnYCo1-X-YO2(X < 0.6, Y > 0), Hai-Lan Feng, Ya-Fei Liu, Yan-Bin Chen

Journal of Electrochemistry

Lithium-rich manganese based cathode materials 0.6Li[Li_1/3Mn_2/3]O₂⋅0.4LiNi_xMn_yCo_1-x-yO₂ (x < 0.6, y > 0) were synthesized by carbonate co-precipitation and high temperature solid-state reaction. The structures and morphologies of the as-prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The results of high temperature in-situ XRD test show that the lattice parameters change significantly with increasing temperature and Ni content. The cation mixing gets serious and the spinel phase appears in the high Ni content samples when the temperature is up to 800 oC. Under voltages ranging from 2.0 to …

Short Review On Electrochemical Energy Storage, Hong Li, Ying-Chun Lyu

Journal of Electrochemistry

Energy storage is a critical supporting technology in many fields such as energy, information, transportation, and healthcare, aerospace, advanced manufacture, advanced equipment, national security. Electrochemical energy storage technique has been widely applied and is developing continuously. In this article, the energy storage mechanism, technical indicators and technology ready level in electrochemical energy storage are summarized. Mainly based on lithium ion batteries, untraditional electrochemical issues in electrochemical energy storage devices are described from the perspective of fundamental science. These issues deal mainly with thermodynamics, kinetics, size effect, asymmetric system, asymmetric reaction path, surface phenomenon, hybrid ion transportation, and solid state battery. …

Latest Progresses In Vanadium Flow Battery Technologies And Applications, Xiao-Li Wang, Yu Zhang, Hua-Min Zhang

Journal of Electrochemistry

With virtues of high safety, long cycle life, friend environment and state of charge easy monitoring, vanadium flow battery has become an effective technique for large scale energy storage. United States, Japan, Europe and other developed countries are actively promoting the developments of vanadium flow battery technology and related equipments. In this paper, the performance of containerized vanadium flow battery, which was newly developed by Rongke Power (RKP) and Dalian Institute of Chemical Physics, was introduced. The operation data of 5 MW/10 MWh vanadium flow battery energy storage station was displayed. Finally, it is pointed out that reducing the cost, …

A Comparative Study Of Polyurethane Nanofibers With Different Patterns And Its Analogous Nanofibers Containing Mwcnts, Javier Macossay-Torres, Faheem A. Sheikh, Hassan Ahmad, Hern Kim, Gary L. Bowlin

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

Tissue engineering is a multidisciplinary field that has evolved in various dimensions in recent years. One of the main aspects in this field is the proper adjustment and final compatibility of implants at the target site of surgery. For this purpose, it is desired to have the materials fabricated at the nanometer scale, since these dimensions will ultimately accelerate the fixation of implants at the cellular level. In this study, electrospun polyurethane nanofibers and their analogous nanofibers containing MWCNTs are introduced for tissue engineering applications. Since MWCNTs agglomerate to form bundles, a high intensity sonication procedure was used to disperse …

Effect Of Adsorption Potential On Co Oxidation At Au@Pt Nanoparticles Electrodes, A Surface Enhanced Raman Spectroscopic Study, Pu Zhang, Yi Wei, Yong-Li Zheng, Yan-Xia Chen, Zhong-Qun Tian

Journal of Electrochemistry

The adsorption/oxidation of CO on the 55 nm [email protected] nm Pt nanoparticles electrode in both potentiodynamic and potentiostatic modes were investigated by surface enhanced Raman spectroscopy in a thin layer electrochemical flow cell under controlled mass transport, with the aim of clarifying the origin CO oxidation at lower electrode potentials (in current pre-wave region of corresponding cyclic voltammograms). Our results demonstrated that the CO oxidation kinetics differed significantly from the three kinds of different CO adsorption history, with almost no CO oxidation current in the pre-peak potential region after 0.35 V_RHE CO adsorption with or without subsequent holding the …

Synthesis And Electrochemical Performance Of Mn3O4/Graphene Composites, Shan-Shan Yang, Qian Zhang, Xiong-Gui Lin, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The Mn₃O₄/Graphene composites were synthesized by hydrothermal method with the in-situ redox reaction of graphene oxide (GO) and manganese acetate (Mn(Ac)₂). The phase structures and morphologies of the materials were characterized by XRD, SEM and TEM. The XPS and IR techniques were used for studying the residual function groups of reduced graphene oxide (RGO). The electrochemical performances of the hybrids were tested in a coin cell. Results showed that the composites prepared with the addition of ammonia water (RM-A) have better performance. The graphenes in RM-A were better-reduced and the Mn₃O_{4 …}

Synthesis, Structure And Electrochemical Performance Of Na2Mnsio4/C Cathode Material For Na-Ion Batteries, Shou-Ding Li, Jiang-Huai Guo, Yong Xie, Jin-Xiao Mi, Yong Yang

Journal of Electrochemistry

As a promising cathode material for sodium ion batteries, pure phase Na₂MnSiO₄/C nanocomposite was successfully synthesized by a sol-gel method with a citric acid as a complex agent. The as prepared material was characterized by XRD, FTIR, SEM and TEM techniques. XRD and Rietveld refinement results indicated that the sample was indexed as monoclinic structure with space group of Pn. It was observed by SEM and TEM that the obtained product consisted of micro-scaled secondary particles, which were composed of NaMnSiO₄ nanocrystallites and amorphous carbon network. More importantly, the uniform carbon network in the …

Tungsten Carbide/Carbon Electrode Material Synthesized By Block Copolymer Template Method, Xiao-Ling Lang, Ye-Kun Jiang, Mei-Qin Shi, Ling-Zhi Kang, Chun-An Ma

Journal of Electrochemistry

At present, one of the major hurdles for commercialization of system with direct methanol fuel cell (DMFC) is still the requirement of a significant amount of platinum (Pt) catalyst to achieve an acceptable power density. Pt and Pt-based metals are expensive due to limited supplies. In order to find the catalyst alternative to the Pt metal, we selected tungsten carbide (WC) and its composites as the study object. We synthesized WC with carbon materials as the suitable support to modify the electronic structure and to increase the specific surface area of WC. In this study, tungsten carbide/carbon (WC/C) was prepared …

Mechanism Study On The Electrocatalytic Oxidation Of Acetylene To Oxalic Acid, Xiu-Li Song, Rui-Long Jia, Wen-Yan Dong, Zhen-Hai Liang

Journal of Electrochemistry

A new method of electrocatalytic synthesis oxalic acid from acetylene was explored and the synthesized oxalic acid was characterized by Ultraviolet-visible spectrophotometry (Uv-vis) and Infrared spectroscopy (IR). First-principles calculations were carried out to examine the adsorption of acetylene over the Pt(111) surface. The electrocatalytic oxidation behavior of acetylene has been investigated on a Pt electrode by cyclic voltammetry (CV) and steady-state polarization in Na₂SO₄ solution. The formation mechanism of oxalic acid in the Na₂SO₄ solution was proposed and the transfer coefficients of the reaction were calculated. The results show that acetylene molecule tends to …

Reaction Mechanisms Study Of Pb Electrodes In Sulfuric Acid And Sodium Sulfate Solutions By Eqcm, Xian-Ping Zou, Zong-Xuan Kang, Yu-Lan Huang, Dong Shu, Ya-Yun Zhong, Jun-Nan Hao, Yu-Qing Liao

Journal of Electrochemistry

Surface reaction processes of Pb electrodes were investigated in H₂SO₄ and Na₂SO₄ solutions by LSV, CV and EQCM. The results in the voltammogram and the mass change curve of the Pb electrode indicated that the oxide products of lead included PbSO4 and PbO·PbSO₄ in sulfuric acid solution with a positive-going potential scan from -1.0 V to -0.4 V and then PbO·PbSO₄ transformed into PbSO₄. However, the oxide product of lead was only PbSO₄ in sodium sulfate solution. The experimental results revealed that the acid solution is necessary for the …