Materials Chemistry Commons^™

Electrochemical Behaviors And Determinations Of Terbutaline Sulfate At Poly Eriochrome Black T Modified Electrode, Yan-Jie Zheng, Hong Yao, Shao-Huang Weng, Hua-Ping Peng, Shi-Wen Gong, Li Huang, Qiang Dai, Xin-Hua Lin

Journal of Electrochemistry

The poly eriochrome black T modified electrode was prepared by electropolymerization. This modified electrode was characterized by scanning electron microscopy(SEM), electrochemical impedance spectroscopy(EIS) and cyclic voltammetry (CV). The electrochemical behaviors of terbutaline sulfate were studied by CV, while the recoveries were measured by differential pulse voltammetry (DPV). The modified electrode shows excellent electrocatalytic characteristics for terbutaline sulfate. In pH 7.0 phosphate buffer solution, the oxidation peak currents obtained by DPV were linear to the terbutaline sulfate concentrations over the range of 1.2x10^-7~2.0x10^-6 mol•L^-1. The detection limit was estimated to be 1.5x10^-8  mol•L^-1 and …

Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, Zhen-Feng Cai, Bing Sun, Wen-Jie Jiang, Ting Chen, Dong Wang, Li-Jun Wan

Journal of Electrochemistry

An electrocatalyst for oxygen reduction reaction (ORR) is an important component for fuel cells. An investigation at interfacial electrochemical reactions toward ORR at a molecular scale benefits mechanistic understanding as well as rational design of catalysts. Scanning tunneling microscopy (STM) has been proven to be a powerful tool to monitor chemical reactions and to provide in-situ information about the interfacial electrochemical reactions at a molecular level. This review summarizes the recent STM studies in monitoring the interface processes such as morphological changes, molecular changes, reaction intermediates, and oxidation products. The prospects of future development in this field are outlined.

Chitosan/Nonahydrate Gel Derived Fe-N-Doped Porous Carbon Sheet As High-Efficient Orr Electrocatalyst, Fan-Lu Meng, Xin-Bo Zhang, Jun-Min Yan

Journal of Electrochemistry

The chitosan/nonahydrate gel was used as a precursor to realize the uniform mixture of N-polymer and metal salt. After lyophilization treatment, the gel went through heat treatment and acid etch. Accordingly, the Fe-N-doped porous carbon sheet with homogenous composition and microstructure was prepared. Compared with the commercial Pt/C catalyst, the Fe-N-doped porous carbon sheet exhibited more positive onset potential and half-wave potential, higher current density, and especially, excellent durability. The power density of 318 mW·cm^-2 was obtained in alkaline fuel cell with the Fe-N-doped porous carbon sheet as a cathode catalyst, which is higher than 267 mW·cm^-2 with …

Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, Hui-Juan Wang

Journal of Electrochemistry

Ultrathin cobalt oxide (Co₃O₄) nanoflakes film material was synthesized by using an electro-deposited cobalt layer as a raw material through a simple oxidation method and followed by a heat treatment at 350 ^oC. The physical characterizations of the Co₃O₄ nanoflakes film were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) technologies, and the electrochemical activity was measured by cyclic voltammetry (CV). As a promising material for electrochemical sensing, the as-synthesized ultrathin Co₃O₄ nanoflakes film material exhibited excellent electrochemical activity for H₂O …

Lithium-Sulfur (Selenium) Batteries: Interface Issues And Solving Strategies, Nian-Wu Li, Ya-Xia Yin, Yu-Guo Guo

Journal of Electrochemistry

The stable interface is still a challenge for lithium-sulfur (selenium) batteries because of the low conductivity of sulfur (selenium), dissolution of polysulfide (polyselenide), volume expansion of sulfur (selenium), and lithium dendrite growth. This review describers some recent developments in lithium-sulfur (selenium) batteries and highlights our efforts in this field. The possible strategies for building stable interface in the lithium-sulfur (selenium) batteries including nano-restriction effect, chemical bonding, interface adsorption, surface coating, electrolyte optimization, and Lithium anode treatment have been discussed.

Intrinsic Interfacial Property Between High-Voltage Lini0.5Mn1.5O4 Cathode And Electrolyte, Li Li, Jing-Jing Xu, Shao-Jie Han, Wei Lu, Li-Wei Chen

Journal of Electrochemistry

To obtain high energy density, developing high-voltage cathode materials is an effective approach. The cathode/electrolyte interface stability is the key factor for the cycle performance and safety performance of high-voltage lithium ion batteries. It is, therefore, of significant importance to study the stability of cathode/electrolyte interface. However, many reports have shown that at the cathode/electrolyte interface the cathodes were prepared by coating the mixture of active materials with a conductive additive and a binder on an Al current collector. The introduction of additives will interfere the surface morphology and component analyses, resulting in difficulty to acquire the intrinsic information at …

Polyol Induced Partitioning Of Essential Oils In Aqueous Organic Solvent Mixtures, Thomas Delmastro

Seton Hall University Dissertations and Theses (ETDs)

Polyol Induced Extraction (PIE) was developed and patented at Seton Hall University by Drs. John R. Sowa Jr., Wyatt R. Murphy, and Mithilesh Deshpande. It was originally discovered and implemented as a method to recycle and reuse waste acetonitrile during the production shortage in 2008. Through the use of PIE, a solvent mixture containing acetonitrile and water can be separated by employing a polyol mass separating agent, which induces a phase separation. The system is separated into its corresponding aqueous and organic phases, with the organic phase being a highly purified organic liquid. Based on the successful experimental results that …

A Grand Unified Model For Liganded Gold Clusters, Wen Wu Xu, Beien Zhu, Xiao Cheng Zeng, Yi Gao

Xiao Cheng Zeng Publications

A grand unified model (GUM) is developed to achieve fundamental understanding of rich structures of all 71 liganded gold clusters reported to date. Inspired by the quark model by which composite particles (for example, protons and neutrons) are formed by combining three quarks (or flavours), here gold atoms are assigned three ‘flavours’ (namely, bottom, middle and top) to represent three possible valence states. The ‘composite particles’ in GUM are categorized into two groups: variants of triangular elementary block Au₃(2e) and tetrahedral elementary block Au₄(2e), all satisfying the duet rule (2e) of the valence shell, akin to …

Design And Synthesis Of Novel Octacarboxy Porphyrinic Metal–Organic Frameworks, Jacob A. Johnson

Department of Chemistry: Dissertations, Theses, and Student Research

Metal-Organic Frameworks (MOFs) are a class of nanoporous crystalline materials constructed via the interconnection between metal-ions/inorganic clusters and organic ligands. Since the surface area, pore size and distribution, and chemical functionalities of MOFs are highly tunable via the judicious combinations of inorganic clusters and organic ligands, MOFs have attracted intensive interests for a variety of applications including gas adsorption and separation, catalysis, chemical sensing, and drug delivery among others. Porphyrin based ligands are of particular interest for building functional MOFs due to their unique photo-, electro-, and catalytic properties. In addition, the four-fold symmetry of porphyrin ligands offers an effective …

Subtractive Methods To Form Pyrite And Sulfide Nanostructures Of Fe, Co, Ni, Cu And Zn, Kurt W. Kolasinski

Chemistry Faculty Publications

The low Z metals Fe, Co, Ni, Cu and Zn are Earth abundant, i.e. inexpensive, and their sulfides are of low toxicity. This makes them appealing candidates for materials applications requiring semiconductors or, in the case of CoS₂, a metal since they can potentially be produced in large quantities and low cost. Though of great potential little work has explored how subtractive methods can be used to form nanostructured and/or porous structures in, e.g. FeS₂, CoS₂, NiS, Cu₂S and ZnS.

Preparation Of Aminoalcohols And Their Application For The Synthesis Of Heterocycles And As Potential Sensors For Nerve Agents, David L. Sellers

Dissertations

Oxazoles and oxazolines are important heterocyclic scaffolds commonly used in pharmaceuticals and optoelectronic materials. Traditionally these heterocyclic compounds are prepared by condensation methodology that suffers from poor reactivity when using electron deficient or sterically crowded reaction partners. Condensation methods also exhibit low tolerance of many functional groups as the reactions typically use strong acids and high temperatures. This dissertation describes an alternate strategy for the formation of these compounds by employing an epoxide opening followed by oxidation to form these heterocyclic compounds.

Epoxide opening reactions with primary aliphatic, allylic, and benzylic amines, aminolysis reactions, often achieve high yields regardless of …

Design And Synthesis Of Dynamic Covalent Polymer Scaffolds With Controlled Architectures, Emily Annette Hoff

Dissertations

The design and synthesis of functional, controlled polymer architectures is essential to the development of new materials with precise and tailorable properties or applications. The work described in this dissertation focuses on the development of controlled polymer architectures with dynamic linkages for the design of multifunctional materials and surfaces via robust, efficient, and stimuli-responsive strategies.

In Chapter III, a post-polymerization modification strategy based on ambient temperature nucleophilic chemical deblocking of polymer scaffolds bearing N-heterocycle blocked isocyanate moieties is reported. Room temperature RAFT polymerization of three azole-N-carboxamide methacrylates, including 3,5-dimethyl pyrazole, imidazole, and 1,2,4-triazole derivatives, afforded reactive polymer scaffolds …

Electrogenerated Chemiluminescence Study Of Semiconductor Nanoparticles Towards Sensitive Detection Of Biomolecules, Yiliyasi Wusimanjiang

Dissertations

The main focus of this dissertation is to unfold the fundamental aspects of electrogenerated chemiluminescence (ECL) generation from semiconductor nanoparticles (also known as quantum dots or QDs) within different ECL systems. The ECL and photo-physical interactions between the CdTe QDs (λ_emission= ~760 nm) and the CdSe QDs (λ_emission= ~550 nm), as well as the effects of carbon nanotubes on ECL of QDs were separately investigated. Optimum experimental conditions for peptide bond formation on an electrode surface through EDC (1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride)/NHS (N-Hydroxysulfosuccinimide) coupling were also revealed using cyclic voltammetry technique. Based on the information …

Role Of The Inner Shell Architecture On The Various Blinking States And Decay Dynamics Of Core-Shell And Core-Multishell Quantum Dots, Pooja Bajwa

Graduate Theses and Dissertations

Colloidal semiconductor nanocrystals (quantum dots, QDs) have received much attention in recent years due to their uniquely size-tunable properties leading to a number of promising applications. Some of their most popular applications include their use as fluorescent probes in biology, as electro-optical components and in photovoltaic devices. CdSe-based QDs are particularly important because of their ease of synthesis, high photoluminescence quantum yields (PL QYs) across the whole visible spectrum and their photostabilty. Shelling of core QDs is usually carried out to improve their optical properties, minimize outer environmental effects on their properties, and avoid toxic element exposure to the environment. …

Graphene Quantum Dots Electrochemistry And Development Of Sensitive Electrochemical Biosensor [Hybrid Poster 1-B], Tyler Smith, Alexander Banaszak

Posters-at-the-Capitol

Graphene quantum dots (GQDs) are zero-dimensional material derived from graphene derivatives with characteristics from the structure of graphene with quantum confinement and edge effects possessing unique properties. Intense research activity in GQDs is attributed to their novel physical-chemical phenomena arising from the sp²-bonded carbon core surrounded with edge functional moieties. In this work, GQDs of optimal 5-7 nm size are investigated for their fundamental electrochemical properties and use in electrochemical sensing including enzyme-based glucose biosensor. Glucose oxidase (GO_x) was immobilized on GQDs modified glassy carbon (GC) and the UV-Vis absorption and fluorescence spectroscopy, electron microscopy, cyclic …

Molecular Sensitivity And Selectivity Of Metal Nanoparticles Decorated Graphene As ‘Smart’ Surface-Enhanced Raman Scattering (Sers) Platforms [Hybrid Poster 1-A], Alexander Banaszak, Tyler Smith

Posters-at-the-Capitol

Raman scattering signal enhancement that uses graphene as support, graphene-enhanced Raman scattering (GERS), is a recent phenomenon. It can produce clean and reproducible Raman signals of chemical molecules with significantly enhanced signal intensity in contrast to traditional surface- (SERS) and tip- enhanced Raman scattering (TERS) techniques. While enhancement in SERS and TERS arise due to the electromagnetic mechanism, GERS also relies on a chemical mechanism and therefore shows unique molecular sensitivity and selectivity. In this work, we developed graphene materials decorated with noble metal (silver and gold) nanoparticles for detection of different chemical molecules e.g. methylene blue (MB) and rhodamine …

Advances And Prospects Of Lithium-Sulfur Batteries, Shou-Yi Yuan, Ying Pang, Li-Na Wang, Yong-Gang Wang, Yong-Yao Xia

Journal of Electrochemistry

Lithium-sulfur batteries have recently attracted worldwide attention due to the high specific theoretical energy density of sulfur cathode (2600 Wh⋅kg^-1), low cost and wide availability of sulfur. However, the practical application of lithium-sulfur batteries has been hindered by several challenges, such as the shuttling of polysulfide intermediates, the large volume expansion of sulfur during charge/discharge and the dendrites formation on lithium anode. Foremost among these is the shuttling effect arising from the dissolution of lithium polysulfides intermediate into the electrolyte from the cathode reaction and their diffusion to the anode where they react with metal lithium to form …

Research Progress In Cycle Stability Of Silicon Based Li-Ion Battery Anodes, Ze-Liang Guo, Hui Wu

Journal of Electrochemistry

Silicon(Si), with the highest specific capacity currently known, is a promising anode material for Li-ion battery. However, in the charging and discharging process, with Li atoms inserting into and breaking out of the Si crystal lattices, the Si anode undergoes enormous volume expansion and contraction, ending in pulverization. The fact that the specific capacity of bulk Si anodes drop quickly is a challenging problem. In this review, we summarize recent progresses in Si anode. We concern about the nanostructure of silicon, cooperation of silicon with other additives and macrostructure design of anodes. We discuss strengths and shortcomings of different methods, …

Effects Of Lithium Salts On The Properties Of Hyperbrandched/Comb-Like Composite Polymer Electrolytes, Xian-Lei Hu, Xiao-Xu Liang, Ming-Qiu Zhang, Ruo-Xin Zhang, Li-Ping Zhang, Wen-Hong Ruan

Journal of Electrochemistry

Based on the chemical characteristics of the hydroxyl group of PVA side-chain, the hyperbrandched poly(amine-ester) (HBPAE) was used to hypergraftingly pretreated nano-silica (SiO₂) and polyving akohol (PVA). And different lithium salts were added to fabricate the SiO₂-g-HBPAE/PVA-g-HBPAE hyperbrandched/comb-like composite polymer electrolytes (CPEs). The dispersion of nanoparticles in matrix was observed by SEM. The effects of different lithium salts on the properties of CPEs were studied by DSC, tensile test and dielectric spectra. The results showed that the hypergrafting method improved the interphase compatibility between SiO₂ and matrix. Sulfonic acid type lithium salts accelerated self-plasticizing with …

The Study Of Dynamical Electrochemical Impedance Spectroscopy For Oxygen Reduction Reaction On Pt/C Catalyst, Kun-Ming Shi, Jian-Wei Guo, Jia Wang

Journal of Electrochemistry

With joint techniques of rotating disc electrode(RDE) and electrochemical impedance spectroscopy(EIS), and further establishment on equivalent circuit model, this paper studied oxygen reduction reaction(ORR) on commercial Pt/C catalyst in acid medium. Our results found that the dynamical interface on Pt/C consists of two independent processes: 1) the PtO reduction from Pt surface, 2) the new PtO formation from ORR, thus providing key clues for catalyst stability and activity. This also implied that the dynamical interface facilitates reconstruction for porous electrode, and matches with mass transfer. One important issue is discovered that at high overpotential, the high reaction rate for ORR …