Chemistry Commons^™

Structural And Dynamic Studies Of Spinel Lini0.5Mn1.5O4Cathode Material During Initial Charge/Discharge Processes, Qin Wang, Li-Li Zhou, Chong-Heng Shen, Qi Wang, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

The spinel LiNi_0.5Mn_1.5O₄ material was synthesized by co-precipitation method with NaOH as a precipitant. The structure and morphology of the as-prepared LiNi_0.5Mn_1.5O₄ materials were characterized by means of XRD, FTIR and SEM. The results indicated that the material belonged to space group and consisted of octahedral particles with the sizes of 3 ~ 6 μm. Electrochemical tests showed the first discharge specific capacity of 121.5 mAh·g^-1 at 0.1C. After 150 cycles, about 99% of reversible capacity was retained for the LiNi_0.5Mn_1.5O₄ material. A combining …

Broadband Sum-Frequency Generation Spectroscopic Invstigations Of Thiocyanate On Polycrystalline Au Electrode In Alkaline Solutions, Mei Xu, Jing-Jing Wang, Zhi-Chao Huangfu, Ng Ying Wa, Yu-Han He, Zhao-Hui Wang

Journal of Electrochemistry

Broadband sum frequency generation (BB-SFG) spectroscopy has been used to investigating the potential-dependent adsorption behaviors of thiocyanate ions on polycrystalline Au electrode in alkaline solutions. During the positive scan, a change in the Stark slope (dω_C-N/dE) for C—N stretching mode can be observed in the range of -1.1 V ~ 0.2 V (vs. SCE), which implies that the orientation of adsorbed thiocyanate ions at Au electrode surface changes from N-bound (dω_C-N/dE=45 cm^-1·V^-1) form to S-bound (dω_C-N/dE = 16.2 cm^-1·V^{-1 …}

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 …

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 …

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 …

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 …

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 …

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 …

The Journal Of Electrochemistry Award 2015, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Homo–Lumo Energy Gap Control In Platinum(Ii) Biphenyl Complexes Containing 2,2′-Bipyridine Ligands, D. Paul Rillema, Stanislav R. Stoyanov, Arvin Cruz Ph.D., Huy Nguyen, Curtis Moore, Wei Huang, Khamis Siam, Ali Jehan, Venugopal Komreddy

Chemistry Faculty Publications

A series of platinum(II) biphenyl 2,2’-bipyridine complexes containing electron-donating and electron-withdrawing moieties on the 4 and 4’ positions of the bipyridine ligand exhibit emission from excited states in the 600 nm region of the spectrum upon excitation in the metal-to-ligand charge transfer transition located near 450 nm. These complexes are distorted from planarity based on both single crystal structure determinations and density functional theory (DFT) calculations of isolated molecules in acetonitrile. The DFT also reveals the geometry of the lowest-lying triplet state (LLTS) of each complex that is important for emission behavior. The LLTS are assigned based on the electron …

Preparation And Radioprotective Effects Of A Standardized Tocotrienol Containing Extract Isolated From Annatto Seeds (Bixa Orellana L.), Edith Nathalie Pineda

Theses and Dissertations

Currently there is no ideal radioprotective agent: one which does not show toxicity, offers long term protective effects, and is easy to administer. In this research we have developed a standardized extract of annatto, Bixa Orellana L, containing a total 60% of delta and gamma tocotrienol, in a 10:1 ratio. The extract was prepared via solvent extraction and chromatography. Radioprotective effects of the standardized extract against total body radiation were determined. Twenty-four hour before radiation CD2F1 mice received a subcutaneous injection of annatto extract a dose of 200 mg/Kg body weight. Experimental groups each received two different single radiation doses …

Dissection Of The Factors Affecting Formation Of A Ch∙∙∙O H-Bond. A Case Study, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations are used to examine how various constituent components of a large molecule contribute to the formation of an internal CH∙∙∙O H-bond. Such a bond is present in the interaction between two amide units, connected together by a series of functional groups. Each group is removed one at a time, so as to monitor the effect of each upon the H-bond, and thereby learn the bare essentials that are necessary for its formation, as well as how its presence affects the overall molecular structure. Also studied is the perturbation caused by change in the length of the aliphatic chain …

Chem & Biochem Celebrate Anniversaries: 75th For Dept; 50th For Lecture Series, Becky St. Clair

Andrews Agenda: Campus News

The Department of Chemistry & Biochemistry celebrated two anniversaries in 2015: The 75th anniversary of the department and the 50th anniversary of the lecture series itself.

Synthesis And Structure−Activity Relationships Of Tambjamines And B‑Ring Functionalized Prodiginines As Potent Antimalarials, Papireddy Kancharla, Jane Xu Kelly, Kevin A. Reynolds

Chemistry Faculty Publications and Presentations

Synthesis and antimalarial activity of 94 novel bipyrrole tambjamines (TAs) and a library of B-ring functionalized tripyrrole prodiginines (PGs) against a panel of Plasmodium falciparum strains are described. The activity and structure–activity relationships demonstrate that the ring-C of PGs can be replaced by an alkylamine, providing for TAs with retained/enhanced potency. Furthermore, ring-B of PGs/TAs can be substituted with short alkyl substitutions at either 4-position (replacement of OMe) or 3- and 4-positions without impacting potency. Eight representative TAs and two PGs have been evaluated for antimalarial activity against multidrug-resistant P. yoelii in mice in the dose range of 5–100 mg/kg …

Fugacity Examples 2: The Fugacity Of A “Hard-Sphere” Semi-Ideal Gas And The Van Der Waals Gas, Carl W. David

Chemistry Education Materials

The fugacity of the van der Waals gas is obtained after a review of the concept itself.

Errata For Tensor Of Moment Of Inertia (52) Manuscript, Carl W. David

Chemistry Education Materials

An error in the manuscript (52) of this series is noted

Identification Of Inhibitors That Target Dual-Specificity Phosphatase 5 Provide New Insights Into The Binding Requirements For The Two Phosphate Pockets, Terrence S. Neumann, Elise A. Span, Kelsey S. Kalous, Robert D. Bongard, Adam Gastonguay, Michael A. Lepley, Raman G. Kutty, Jaladhi Nayak, Chris Bohl, Rachel G. Lange, Majher I. Sarker, Marat R. Talipov, Rajendra Rathore, Ramani Ramchandran, Daniel S. Sem

Chemistry Faculty Research and Publications

Background: Dual-specificity phosphatase-5 (DUSP5) plays a central role in vascular development and disease. We present a p-nitrophenol phosphate (pNPP) based enzymatic assay to screen for inhibitors of the phosphatase domain of DUSP5.

Methods: pNPP is a mimic of the phosphorylated tyrosine on the ERK2 substrate (pERK2) and binds the DUSP5 phosphatase domain with a Km of 7.6 ± 0.4 mM. Docking followed by inhibitor verification using the pNPP assay identified a series of polysulfonated aromatic inhibitors that occupy the DUSP5 active site in the region that is likely occupied by the dual-phosphorylated ERK2 substrate tripeptide (pThr-Glu-pTyr). Secondary assays …

Carbide-Derived Carbon By Electrochemical Etching Of Vanadium Carbides, Luis G.B. Camargo, Benjamin G. Palazzo, Greg Taylor, Zach A. Norris, Yash K. Patel, Jeffrey D. Hettinger, Lei Yu

College of Science & Mathematics Departmental Research

Carbide-derived Carbon (CDC) has been demonstrated to be an excellent electrode material for electrochemical devices including supercapacitors due to its chemical and electrochemical stability, large specific surface area and controllable pore size and morphology. Currently, CDC is prepared from metal carbides by chlorination in a chlorine gas atmosphere at temperatures of 350°C or higher. In this paper, conversion using electrochemical methods is reported, which can be achieved by oxidizing vanadium carbides (VC or V₂C) in aqueous solutions at room temperature and a mild electrode potential to prepare CDC thin film as electrode materials for “on-chip” supercapacitiors. It was …

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 …

Understanding The Backlog Problems Associated With Requests For Continued Examination Practice, Sean Tu

Duke Law & Technology Review

One of the greatest problems facing the current patent administration is a long patent pendency period. This study focuses on Request for Continued Examination (RCE) practice, and its effects on the current patent application backlog problem. RCEs are used to continue prosecution after a patent examiner has issued a final rejection. However, now that RCEs are placed on an examiner’s special docket, some examiners may pick up prosecution one to two years after the last action. Accordingly, there are great inefficiencies that may be created by this delay, such as relearning issues and questions from the previous action, diminished value …

Screening Protein Ligand Interactions Using Microelectrode Arrays, Sakshi Uppal

Arts & Sciences Graduate Student Theses and Dissertations

G proteins comprising of α subunit and βγ dimer are signaling proteins that play essentialroles in various pathological conditions. Direct modulation of these G proteins (specifically Gα subunit) using small chemical probes to elucidate their acute function is of great value. YM-254890 is a small molecule which is the first selective inhibitor of a class of G proteins, Gαq. However, despite its biological importance, this molecule is not available to researchers. In addition, the complex core structure of this cyclic depsipeptide has thwarted efforts to obtain a series of analogs by total synthesis. Moeller lab sought to overcome this obstacle …

Solid-State Nmr Studies Of Carbon Capture And Carbon Mineralization Reactions, Jeremy Moore

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation presents research on the chemistry of carbon dioxide capture and mineralization which has been accomplished with a variety of solid-state nuclear magnetic resonance (NMR) spectroscopy techniques. Materials used for carbon capture interact with CO2 through different adsorption mechanisms, physisorption and chemisorption. The physisorption systems studied have shown that adsorbed CO2 undergoes a hopping mechanism within the material. The studies of chemisorption systems indicate a mixture of adsorption products forms during the adsorption interaction. Carbon mineralization reactions have been studied to better understand the reactions that can occur at underground carbon sequestrations sites that are used for storing CO2. …

Structural And Functional Analysis Of The Reaction Center Complexes From The Photosynthetic Green Sulfur Bacteria, Guannan He

Arts & Sciences Graduate Student Theses and Dissertations

The reaction center (RC) complex of the green sulfur bacterium Chlorobaculum tepidum is composed of the Fenna-Matthews-Olson (FMO) antenna protein and the reaction center core (RCC) complex. The RCC complex has four subunits: PscA, PscB, PscC, and PscD. The structure of the intact and functional FMO-RCC complex was studied by chemically cross-linking the purified sample followed by biochemical and spectroscopic analysis. The interaction sites of the cross-linked complex were also studied using LC-MS/MS. A structural model is proposed based on those results. In addition, the RCC complexes were purified, both the PscA-PscC complex from the Chlorobaculum tepidum and the PscA-PscB …

Manipulating Electron Transfer Reactions From Micro- To Preparative Scale, Matthew Duane Graaf

Arts & Sciences Graduate Student Theses and Dissertations

The utilization of electron transfer reactions has allowed the transformation of a variety of substrates from polymer surfaces to highly functionalized organic molecules. The intricacies of these electron transfer reactions have been utilized to develop a new platform for building and studying addressable molecular libraries as they interact with biological targets. As a low cost, reusable alternative to other methods of these studying binding interactions, microelectrode arrays are beginning to gain traction with the scientific community as we continually push the limits of their potential. Additionally, the electron transfer techniques used to build the molecular libraries can be expanded to …

Structure And Function Of Cytochrome Containing Electron Transport Chain Proteins From Anoxygenic Photosynthetic Bacteria, Erica Lois-Wunderlich Majumder

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation examines the structure and function of photosynthetic proteins that contain c-type heme cofactors that function in the electron transport chains of anaerobic phototrophic bacteria. The diversity and range of these cytochromes proteins was explored. Then, individual proteins were studied in detail. The diheme cytochrome c from Heliobacteria modesticaldum was studied using hydrogen deuterium exchange mass spectrometry and homology modeling. A structural model of the protein and a mechanism for the cytochrome bc complex was proposed. Next, the monoheme cytochrome c subunit from the Alternative Complex III from the Filamentous Anoxygenic Phototrophs was studied using biochemistry and found to …