Materials Chemistry Commons^™

Electrochemical Removal Of Low Concentration Pb(Ii) From Aqueous Solution Based On Ppy/α-Zrp/Ptcf Electrode, Ru-Yi Chen, Peng-Le Zhang, Sen-Liang Liao, Zhong-De Wang, Xiao-Gang Hao

Journal of Electrochemistry

A novel organic-inorganic hybrid film consisting of polypyrrole/α-zirconium phosphate (PPy/α-ZrP) was prepared in an aqueous phase by cyclic voltammetry method. It was proved by FT-IR, XRD and XPS characterizations that the electroactive PPy/α-ZrP hybrid film was synthesized successfully. The PPy/α-ZrP film electrode prepared on a porous three-dimensional carbon felt (PTCF) was used for removal of a low concentration of Pb(II) ions from an aqueous solution by electrochemically switched ion exchange (ESIX). A quick uptake and release rate of Pb(II) onto the film electrode was obtained by adjusting redox state of the hybrid film. The removal efficiency and adsorption capacity of …

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 …

Preparation And Enhanced Rate Capability Of Spinel Limn1.9Al0.1O3.95F0.05, Jun-Yan Hu, Meng-Meng Wang, Hong-Tao Liu

Journal of Electrochemistry

Spinel LiMn_1.9Al_0.1O_3.95F_0.05 cathode materials with good crystallinity were synthesized by a sol-gel process followed with a high-temperature solid reaction. The effects of partial substitution of Al for Mn, and F for O on the structure and the electrochemical performance were investigated. The results showed that LiMn_1.9Al_0.1O_3.95F_0.05 exhibited the same crystalline state as LiMn₂O₄, but much better electrochemical stability at higher rate cycling. As a result, LiMn_1.9Al_0.1O_3.95F_0.05 could maintain stable electrochemical lithium storage even suffering from …

Sodium Difluoro(Oxalato)Borate As An Electrolyte Additive To Improve The Electrochemical Performance Of Graphite Anode, Yang-Yang Yao, Dong-Dong Liu, Li Wang, Xiang-Ming He, Jian-Jun Li, Ding Zhang

Journal of Electrochemistry

The fast development in applications of Li-ion batteries (LiBs) in daily life urges for better electrochemical performance of LiBs, which can be promoted by adding appropriate electrolyte additives. This work studied the effect of NaDFOB as the additive on a common electrolyte formula (1 mol·L^-1 LiPF₆ in EC+DMC+EMC, 1:1:1 by volume). Analysis methods such as CV, EIS and SEM were adopted to study electrochemical performance of experimental battery and interface profiles. It was revealed that the reversible charge-discharge capacity and cycling performance of graphite anode had been dramatically improved. In addition, the cycling performance of graphite anode at …

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 …

An Investigation On Electrochemical Performance Of Supercapacitor Electrode Materials Prepared By Mno2 With Four Different Crystal Forms, Zhen-Kun Wei, Xiao-Zhen Hua, Ke Xiao, Xian-Liang Zhou, Zhi-Guo Ye

Journal of Electrochemistry

Four types of α-MnO₂, β-MnO₂, γ-MnO₂ and δ-MnO₂ powders were synthesized by relatively simple methods. The differences in crystal structures and surface morphologies for these forms of MnO₂ were investigated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA) and specific surface area analysis (BET). The electrochemical performances were characterized by cyclic voltammetry (CV) and stability analysis. Based on the experimental results, four kinds of MnO₂ electrodes showed good capacity properties, and the α-MnO₂ electrode had the largest specific capacity due to the highest specific surface …

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 …

Preparation And Characterization Of Carbon Supported Pd-Sb Composite Nanocatalysts For Formic Acid Electrooxidation, Long-Long Wang, Xiao-Lu Cao, Ya-Jun Wang, Jin-Hao Ping, Qiao-Xia Li

Journal of Electrochemistry

Palladium is considered as an efficient anode catalyst with high catalytic activity for electrooxidation of formic acid. To further improve the catalytic activity and stability, alloying or surface modification with Sb is an effective way. In this work, the well dispersed carbon supported Pd-Sb composite nanocatalysts (Pd-Sb/C) were synthesized by traditional impregnation reduction method with trisodium citrate as the complexing agent, sodium borohydride as the reducing agent. The morphologies of Pd-Sb/C and the effects of molar ratio of Pd to Sb on the electrocatalytic properties of Pd-Sb/C for HCOOH electrooxidation were studied. The XRD and XPS analyses on the as-prepared …

Effect Of Carbon Nanotubes On Anodic Properties Of Ti/Ru-Ir-Sn Oxides, Feng Lian, Yong-Lei Xin, Bo-Jiang Ma, Li-Kun Xu

Journal of Electrochemistry

The Ru-Ir-Sn metal oxide anodes coated on titanium (Ti/Ru-Ir-Sn) were prepared by thermal decomposition. The effects of amounts of carbon naotubes (CNTs) on anodic properties were studied by TGA, SEM, EDS, cyclic voltammetry, EIS, polarization measurements and accelerated life test. The thermogravimetric analysis and EDS spectrum data showed that the high temperature oxidation decomposition of CNTs did not take place under the condition of the sintering temperature of 470 ℃, and the CNTS still existed in the anode coating in an element form. Compared with the contrast samples, the surface crack of the coating increased, but remained typical morphology. Adding …

Fluorinated Metallo Phthalocyanines For Chemical And Biological Catalysis, Hemantbhai H. Patel

Seton Hall University Dissertations and Theses (ETDs)

The rational design of robust oxidation catalysts based on organic molecules is hindered by the presence of labile C-H bonds. We have shown recently that replacing all C-H bonds by a combination of fluoro- and perfluoro-groups in a bioinspired Cytochrome P450 model based on a phthalocyanine, Pc, scaffold results in a stable yet reactive oxidation catalyst. The Pc cobalt complex catalyzes, for example, the aerobic oxidation of thiols to disulfides, a reaction of both biological significance and industrial importance.

The presence of robust C-F bonds, however, renders the catalyst unsuitable for attachment to solid-state supports, except via van der Waals …

From Copper Zinc Tin Sulfur To Perovskites: Fabrication And Characterization Of New Generation Of Solar Cells, Sarah Wozny

LSU New Orleans Theses and Dissertations

In 2013, the worldwide production of renewable electricity accounted for 22.1% of the total energy production with 0.9% coming from solar photovoltaics (PVs). Recently, there has been a growing interest for Cu₂ZnSnS₄ (CZTS) quaternary semiconductor due to the abundance and low cost of its precursors. Moreover, this chalcopyrite material has an ideal direct band gap around 1.5 eV, high absorption coefficient (α >10⁴ cm^-1) and high conductivity, making it suitable for nanostructured and dye-sensitized solar cell (DSSC) applications. Here, CZTS nanoparticles have been synthesized by pulsed laser deposition (PLD) and simultaneously deposited in the …

Hexaniobate Nanopeapods: In Situ Deposition Of Magnetic-Noble Metal Nanoparticles Inside Preformed Nanoscrolls, Sarah P. Gauthier

LSU New Orleans Theses and Dissertations

An in situ deposition procedure was developed for the nanopeapod (NPP) formation of NiAu nanoparticles inside preformed acid-exchanged hexaniobate nanoscrolls (HNB). Metal salt precursors of Ni(acac)₂ and HAuCl₄∙3H₂O were reduced in solution under mild synthetic conditions in the presence of the preformed acid-exchanged hexaniobate nanoscrolls. Two of the surfactants used for the formation of the nanoparticles were oleylamine and triphenylphosphine oxide (TTPO). Reaction conditions were studied and modified to produce well-defined NiAu@HNB NPP systems, with monodispersed particles evenly filling and orienting within the nanoscrolls. The synthetic parameters studied were both time and temperature, with the …

Bio-Inspired Composite Hydrogels For Osteochondral Regenerative Engineering, Grant N. Gellert, Liangju Kuang, Chunhui Jiang, Nur P. Damayanti, Joseph Irudayaraj, Meng Deng

The Summer Undergraduate Research Fellowship (SURF) Symposium

Treatment of osteochondral defects encompassing injury or degeneration to both the articular cartilage as well as the underlying subchondral bone presents a significant medical challenge. Current treatment options including autografts and allografts suffer from limited availability and risk of immunogenicity, respectively. The long term goal of this work is to develop an integrated scaffold system for treatment of osteochondral defects via in situ regeneration of bone, cartilage and the bone-cartilage interface. Hydrogels composed of polymer networks swollen in water provide an attractive biomaterial platform for regeneration of cartilage. In the present study, we have developed a novel composite hydrogel consisting …

Analysis Of The Fabrication Conditions In Organic Field-Effect Transistors, Rachel M. Rahn, Yan Zhao, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polymer-based organic field-effect transistors have raised substantial awareness because they enable low-cost, solution processing techniques, and have the potential to be implemented in flexible, disposable organic electronic devices. The performance of these devices is highly dependent on the processing conditions, as well as the intrinsic properties of the polymer. Processing conditions play an important role in semiconductor film formation and device performance. These factors may provide an important link between structure and performance. In this study, an empirical analysis tool, Process Scout, was applied to assess processing factors such as polymer concentration and silicon modification. This sanctioned the creation of …

Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou

STAR Program Research Presentations

Metal organic frameworks (MOFs) are synthetic materials made of a cage-like lattice of metal nodes connected by organic linkers. The pores between the nodes define the characteristics of the material. A MOF, MIL-101, has shown great capacity in the adsorption of carbon dioxide and methane, as well as in hydrogenation catalysis with palladium. While there has been success in synthesizing MIL-101 and other MOFs, the mechanistic details behind their assembly remain unknown. Understanding the synthesis mechanism is necessary to understand the kinetics involved and be able to produce this useful material on an industrial scale. Using MIL-101 as a prototypical …

Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Low energy surfaces can strongly repel both oil and water. Recently these surfaces have been fabricated on various substrates including fabric, aluminum, stainless steel and many other materials. In this experiment we explore the use of low energy surface deposition on aluminum alloy, stainless steel and silicon substrates, to enhance the drying rate of liquids removed from the surface by forced convection. We control surface roughness by substrate abrasion and by the growth of Al₂O₃ nanograss to enhance liquid repellence by use of a hierarchical texture. Liquid repellence of the substrates is measured by contact angles of …

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Chemistry Faculty Publications

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing …

Three-Dimensional Scaffolds Of Graphene, Carbon Nanotubes And Transition-Metal Oxides For Applications In Electronics, Sensors And Energy Storage, Gilbert N. Mbah

Department of Chemistry: Dissertations, Theses, and Student Research

Electronics, sensors and energy storage devices are the new waves behind economic development, security and communication¹. Engineering small sizes of electronic, sensors and energy storage devices is the hurdle limiting efficient, portable and vast applications of Nano-devices for economic, security and communication advancement². Silicon the major material used in transistors has approached its limit to fabricated Nano-devices³. The discovery of free standing, one atomic layer thick and two-dimensional graphene sheets with high conductivity, inert, high specific surface area, stable and high tensile strength material in 2004 has shown capabilities to replaced silicon in electronics, …

Dft Analysis Into The Intermediates Of Nickel Pyridenthiolate Catalysed Proton Reduction, Carolyn N. Virca, Theresa M. Mccormick

Chemistry Faculty Publications and Presentations

Nickel pyridine 2-thiolate (Ni(PyS)₃ −) has shown good stability and activity as a H₂ generation catalyst for use in solar energy storage. The experimentally proposed catalytic pathway is explored using DFT calculations. Free energy changes along the reaction coordinate, spin states, localization of charge and geometry of the intermediates were explored. Calculations were performed using Gaussian 09 with a B3P86/ 6-31+G(d) basis set and a CPCM water solvation model. Of particular interest were our findings that the first reduction occurs at the nickel rather than through non-innocent ligands and that water coordination is not favourable although protonation of …

The Quantum Efficiency Of Cdse Semiconducting Nanocrystals, Charles Bledsoe

Undergraduate Theses

CdSe molecules are semiconducting nanocrystals that absorb visible light and emit broad wavelengths of light in response. They utilize electromagnetic radiation not only for emitting broad wavelengths of visible light, but for fluorescence, conducting electricity, and vibrational relaxation. The Thermal Lensing technique (TL) can be used to study the lifetimes of the excited state transitions and the various nonradiative processes molecules can undergo in order to better understand the excited state dynamics of semiconducting nanocrystals, and in turn, better understand how these molecules may be applied in solar cells, lasers, and fluorescence labeling. Using known methods, four samples of CdSe …