Chemistry Commons^™

Preface To Special Issue On Electrocatalysis And Electrosynthesis, Fang-Yi Cheng, Shuang-Yin Wang, Tian-Hua Zhou

Journal of Electrochemistry

No abstract provided.

Advances And Challenges On Cathode Catalysts For Lithium-Oxygen Batteries, Bo Wen, Zhuo Zhu, Fu-Jun Li

Journal of Electrochemistry

Aprotic lithium-oxygen batteries (LOBs) with high theoretical energy density have received considerable attention over the past years. However, the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) at cathodes suffer from slow kinetics for large overvoltages in LOBs. Significant advances on catalysts have been achieved to accelerate cathode kinetics, but understanding on the formation/decomposition processes of Li₂O₂ is limited. Herein, this review highlights the fundamental understanding of the correlation between catalysts and formation/decomposition of Li₂O₂. Various types of cathode catalysts are discussed to reveal the mechanism of formation/decomposition of Li₂O₂, …

Coreflooding Evaluation Of Fiber-Assisted Recrosslinkable Preformed Particle Gel Using An Open Fracture Model, Shuda Zhao, Ali Al Brahim, Junchen Liu, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Recrosslinkable Preformed Particle Gels (RPPGs) Have Been Used to Treat the Problem of Void Space Conduits (VSC) and repair the "Short-Circuited" Waterflood in Alaska's West Sak Field. Field Results Showed a 23% Increase in Success Rates over Typical Preformed Particle Gel (PPG) Treatments. in This Paper, We Evaluated Whether Adding Fiber into RPPGs Can Increase the RPPG Plugging Efficiency and Thus Further Improve the Success Rate. We Designed Open Fracture Models to Represent vs.C and Investigated the Effect of Swelling Ratio (SR), Fracture Size, and Fiber Concentration on Gel Injection Pressure, Water Breakthrough Pressure, and Permeability Reduction. Results Show that …

Design And Applications Of Fmoc-Histidine And Aspartic Acid Tripeptides As Proton Conductive Materials, Shejla S. Pollozi

Dissertations, Theses, and Capstone Projects

The increasing demand for clean and sustainable energy has driven forward rapid improvements in polymer-electrolyte fuel cells and the use of ion-conducting polymers (ionomers) as proton exchange membranes and catalyst binders. While perfluorinated electrolytes have been commercially used as conductive membranes for nearly four decades, a new class of sustainable, conductive materials has emerged, inspired by the efficiency of charge transport processes in biological systems. These molecules, knows as peptide amphiphiles (PAs), have gained popularity as building blocks for the bottom-up fabrication of nanomaterials through supramolecular self-assembly. Supramolecular nanostructures, often in the form of hydrogels, are held together via non-covalent …

Nanoscale Imaging Of Electrocatalytic Nanomaterials By High-Resolution Scanning Electrochemical Microscopy, Xiang Wang

Dissertations, Theses, and Capstone Projects

Numerous insights of the structure–electrochemical activity relationship of nanocatalysts have been obtained by using macroscopic electrochemical measurements over the last several decades. However, signals measured by large electrodes are inevitably averaged out of many nanocatalysts, non-uniformed sizes, uneven morphologies, and multiple crystallographic facets. Over the last ten years, Scanning Electrochemical Microscopy (SECM) has advanced electrochemical measurements toward micro- to nanoscale level at a high spatial resolution. The advantages of using nanoelectrode in SECM include fast mass transfer of reactive species, dominated radial diffusion pattern, small double layer capacitance and small RC constant. In this thesis, high-resolution SECM is applied to …

Engineered Plga Nanofibers For Drug Delivery, Andrew Mancuso

Dissertations, Theses, and Capstone Projects

Poly-lactic-co-glycolic acid (PLGA) polymers are rapidly gaining momentum as a platform for next-generation drug delivery systems due to their ease and low cost of synthesis, favorable biocompatibility and biodegradability, and lack of toxicity. In particular, the application of drug-loaded PLGA nanofibers directly to a target tissue may represent a promising alternative to traditional routes of drug administration (e.g., oral, injectable) as they offer the potential to greatly improve bioavailability, increase efficacy, and reduce off-target toxicity. Furthermore, the use of such a system may potentially allow for greater flexibility in clinical drug development, by enabling the use of compounds which have …

Synthesis And Biomedical Applications Of Hollow Iron Oxide Nanoparticles, Aloka S. Paragoda Arachchilage

Dissertations, Theses, and Capstone Projects

Nano-scale materials have gained much attention during the past few decades due to the stark differences in their properties compared to bulk material. Thus, they are being studied for a myriad of applications ranging from harnessing solar energy to diagnostics. This thesis focuses on the synthesis of hollow iron oxide nanoparticles using Galvanic replacement reactions and their application in drug delivery. Moreover, the use of a peptide precursor for the enhancement of exosomes is also discussed.

Chapter 1 discusses a simple and economical Galvanic approach used for the synthesis of hollow one-dimensional iron oxide nanotubes. In the initial reaction, the …

Carbon Dioxide Capture Potential Of Chitosan-Nanocrystalline Cellulose Aerogel Composite Materials: Synthesis, Functionalization, And Characterization, Victor Oghenekohwo

Theses and Dissertations

The carbon dioxide capture technology has been established as an invaluable player in the current global efforts to allay the warming of the planet and climate change. In this connection, the study centers on the valorization of waste organic materials for the application described herein. The sorbents, sourced from a combination of by-products of food processing and agricultural residue waste products, viz. seafood waste and sugarcane bagasse, showed prospects for selective carbon dioxide capture, adsorbing up to 5.78 mg/g of the gas at 273 K and 2.82 mg/g at 298 K, as observed on the Micromeritic ASAP 2020 surface area …

Recent Advances In Exploring Highly Active & Durable Pgm-Free Oxygen Reduction Catalysts, Yuan Li, Miao-Ying Chen, Bang-An Lu, Jia-Nan Zhang

Journal of Electrochemistry

In order to reduce the considerable usage of expensive but scarce platinum at the cathode in proton exchange membrane fuel cells (PEMFCs), it is necessary to pursue alternatives to platinum. The most promising platinum group metal (PGM)-free catalysts for oxygen reduction reaction (ORR) are atomically dispersed, and nitrogen-coordinated metal site catalysts denoted as M-N-C (M = Fe, Co, or Mn, etc.). Over the last few decades, there have been great advances in these catalysts with high ORR activity and promising initial fuel cell performance approaching traditional Pt/C catalysts. However, the stability of these highly active Fe-N-C catalysts under practical fuel …

Electrochemical Oxidation Of Ethylene On Palladium Electrode, Wei-Xing Wu, Ying Wang

Journal of Electrochemistry

The electrochemical oxidation of C₂H₄ is attracting increasing attention due to its vast potential market. The current electrochemical methods rely on the use of redox mediators, which may produce corrosive intermediates, while direct oxidation is still limited by its low activity and selectivity. Herein, we conducted electrochemical studies to obtain mechanistic insights into the benchmark Pd catalyst. The generated Pd(II) could be the active site for C₂H₄ oxidation. By designing the pulse sequence, we found the ratio of strongly and weakly adsorbed C₂H₄ on Pd to be 0.3:1. The result we …

Preface To Special Issue: Electrocatalysis And Electrosynthesis, Fang-Yi Cheng, Shuang-Yin Wang, Tian-Hua Zhou

Journal of Electrochemistry

No abstract provided.

Supperlattice-Like Structure: Ordered Mass Transfer Endowing High Quality Output Of Fuel Cell, Jian Wang, Wen-Hui Xuan, Qian He, Jing-Xia Jiang, Yuan-Yuan Zhou, Yao Nie, Qiang Liao, Min-Hua Shao, Wei Ding, Zi-Dong Wei

Journal of Electrochemistry

The current or voltage fluctuation in fuel cell operation is harmful to the fuel cell system and power application equipment. Here, we report a technique to eliminate such a fluctuation by the aid of new type of catalysts, superlattice-like mesoporous PtCo catalysts. The current fluctuation in fuel cells catalyzed by two invented catalysts are fixed at as low as 25 mA·cm⁻² with a power of 0.75 W·cm⁻² or 120 mA·cm⁻² with a power of 1.01 W·cm⁻², and no noticeable current decay was detected over 100 h. By contrast, a …

Magnetic Interactions In Open-Shell Conjugated Polymers, Michael Steelman

Dissertations

Most materials are closed shell in which every electron participates in a bond, resulting in unremarkable magnetometry signatures and functionalities. While rare, modern technologies rely on magnetic materials in which unpaired electrons are localized to inorganic atomic centers. In recent decades, a collection of organic open-shell π-conjugated molecules have shown magnetic ordering, albeit at exceedingly low temperatures; a result of weak noncovalent intermolecular interactions limiting long range electronic exchange. Thus, practically applicable sp orbital magnetism that persists at or above room temperature remains a grand challenge for chemistry and physics. Despite the wide variety of chemical structures afforded by organic …

Development Of Battery Materials To Function As Corrosion Protection On Car Body Plates, Tubagus Noor Rohmannudin, Sulistijono Sulistijono, Noval Adrinanda, Faridz Wira Dharma, Samuel Areliano

Journal of Materials Exploration and Findings

Most car bodies made for mass production are made from steel or aluminum. Both are strong metals, but steel is cheaper than aluminum and is more commonly used in lower-end cars for a broader consumer range. The weakness of steel compared to aluminum is that it is susceptible to corrosion under certain conditions, and thus it may deteriorate over time without proper care. To prevent corrosion, modern cars are coated with paint to prevent direct contact with the environment. As a second line of protection, a car battery can be connected to the body to create an impressed current cathodic …

Potential Of Biduri Fiber (Calotropis Gigantea) As Material For Oil Spill Absorbent, Anne Sukmawati, Wulan Septiani

Journal of Materials Exploration and Findings

Biduri fiber (Calotropis gigantea) is a natural hollow fiber with hydrophobic and oleophilic properties potentially used as oil spilled sorbent from seawater. This study aims to determine the absorption capacity and efficiency of the Biduri fiber and membrane to fuel oil. Measurement of oil absorption to seawater was carried out at various fiber weights (0.5-1.5 g), fiber composition (50-95%), contact time (10-90 minutes), temperature (30 and 50°C), and compared with commercial products. The results showed that the fiber weight variation of 0.5-1.5 g has an average absorption efficiency of 96.67%, and the highest absorption was obtained in a weight of …

Influence Of Synthesis Conditions On The Physicochemical And Electrocatalytic Properties Of Non-Stoichiometric Ba2sr2la2ti4o12 Perovskites, Ofeliya Kostadinova, Iliyan Popov, Simeon M. Stankov, Hristo Kolev, Tamara Petkov

Karbala International Journal of Modern Science

Present work studies the influence of the pretreatment milling media (deionized water (BLTOS-H) and isopropanol (BLTOS-i)) on the surface characteristics, structure, chemical composition and catalytic activity of non-stoichiometric Ba2Sr2La2Ti4O12 perovskites. The IR spectroscopy and XRD analyses shows a difference in the structure and phase composition of the two materials. X-ray photoelectron spectroscopy detects a Ba2+- and La3+-enriched and Sr2+-depleted surface. The BLTOS-i sample appears to exhibit higher specific surface area (SSA) and pore volume in comparison to BLTOS-H. The electrochemical tests showed that BLTOS-H sample have similar behavior to platinum at current densi-ties up to 10 mA cm-2, while BLTOS-i …

Dual Ionic Liquid-Functionalized Cellulosic Materials: Thermal, Mechanical And Conductive Properties, Elizabeth Mcgrew, Kevin M. Miller Phd

Posters-at-the-Capitol

Cellulose, an inexpensive and renewable biomacromolecule, represents an intriguing synthetic foundation for new materials with task-specific properties. Here, we wish to report a synthetic route for functionalizing cellulose with a side chain containing two ionic liquid functional groups using azide-alkyne ‘click’ cyclization strategy, followed by quaternization of the two resulting heterocycles (1,2,3-triazole and imidazole). Through this functionalization strategy, the resulting cellulosic materials exhibited significant softening, with several glass transition (T_g) values observed below room temperature, indicating the amorphous nature of the materials, with the T_g dependent on both the length of the side chain and the …

Synthesis Of A Novel Terbium(Iii) Complex For Application In Metal Nanoparticle Surface Modification, Lauralee E. Hurst, Davon Ferrara, Justin Stace

Science University Research Symposium (SURS)

Lanthanide ions, such as terbium(III), exhibit bright luminescence when bound to organic ligands which strongly absorb light. This property has been used in creating chemical sensors or luminescent tags for microscopy. Complexes centered with terbium(III) exhibit a yellow-green luminescence upon excitation by shortwave ultraviolet light. In this work, a bifunctional ligand, 4-mercaptobenzoic acid (4mba), was chosen to selectively coordinate terbium(III) to the oxygens of the acid functional group, leaving the thiol group available for another compound. Thiol groups are effectively used in surface coordination to noble metal nanoparticles (NP). In efforts to create a novel 4mba-terbium(III)-NP system, a one pot …

A Comparison Of Tung Oil Resin Reinforcements Using Fibrous Proteins And Peptides For Biological And Materials Applications, Parker L. Williams

College of Graduate Studies: Theses & Dissertations

In this study a tung oil based thermoset was reinforced with collagen and fibroin, and the resulting composites were analyzed for their physical properties. Tung tree seed oil is a great candidate for biobased polymer production because its triglycerides are primarily made of alpha eleostearic acid, a fatty acid with three conjugated carbon-carbon double bonds. These double bonds allow for mechanically strong crosslinking in the polymer. It has been observed that polymerized tung oil forms a gel. This issue has been addressed using divinylbenzene (DVB) and n-butyl methacrylate (BMA) as co-monomers. Similar bio-based polymers have been studied and tend to …

Using Superatomic Clusters And Charge Transfer Ligands To Control Electronic Characteristics Of Phosphorene Nanoribbons And Phosphorene Monolayer, Ryan Lambert

Theses and Dissertations

Phosphorene is a two-dimensional electron poor p-type semiconductor with high carrier mobility and great promise for applications in electronics and optoelectronics. As the main theme in this dissertation, the following work represents different investigations of various electronic properties associated with phosphorene. Most notable are the findings on charge transfer doping with metal-chalcogenide superatoms which displays novel control of the two most important properties of a semiconductor – the band gap energy and the nature of carriers. By tuning the width of the gap and p-/n-type character of conduction, we gain control over a material’s capacity to play a certain role …

Nanostructured Ternary Nickel-Based Mixed Anionic (Telluro)-Selenide As A Superior Catalyst For Oxygen Evolution Reaction, Ibrahim Munkaila Abdullahi, Siby Thomas, Alessio Gagliardi, Mohsen Asle Zaeem, Manashi Nath

Chemistry Faculty Research & Creative Works

Developing Protocols for Designing High-Efficiency, Durable, Cost-Effective Electrocatalysts for Oxygen Evolution Reaction (OER) Necessitates Deeper Understanding of Structure–property Correlation as a Function of Composition. Herein, It Has Been Demonstrated that Incorporating Tellurium into Binary Nickel Chalcogenide (NiSe) and Creating a Mixed Anionic Phase Perturbs its Electronic Structure and Significantly Enhances the OER Activity. a Series of Nanostructured Nickel Chalcogenides Comprising a Layer-By-Layer Morphology Along with Mixed Anionic Ternary Phase Are Grown in Situ on Nickel Foam with Varying Morphological Textures using Simple Hydrothermal Synthesis Route. Comprehensive X-Ray Diffraction, X-Ray Photoelectron Spectroscopy, and in Situ Raman Spectroscopy Analysis Confirms the Formation …

Diethoxycarbonyl-Bodipys As Heavy-Atom-Free Photosensitizers For Holographic Recording In Cellulose Acetate Photopolymer, Aimee Sheehan, Tatsiana Mikulchyk, Catherine S.P. De Castro, Safakath Karuthedath, Wejdan Althobaiti, Metodej Dvoracek, Sabad-E Gul, Hugh Byrne, FréDéRic Laquai, Izabela Naydenova, Mikhail Filatov

Articles

A series of new heavy-atom-free photosensitizers based on 2,6-diethoxycarbonyl-BODIPY scaffold was designed and applied for holographic recording in a photopolymerizable material. Photoinduced electron transfer between the BODIPY and meso-aryl subunits, followed by the formation of BODIPY triplet excited states via spin-orbit charge transfer intersystem crossing (SOCT-ISC) was studied by steady-state and ultrafast pump-probe transient optical spectroscopy. Highly efficient photosensitization was observed for dyads bearing pyrene and anthracene substituents, which exhibited singlet oxygen generation quantum yields () of up to 94%. Charge transfer and SOCT-ISC were observed in non-polar solvent (toluene) due to the increased electron accepting ability of the diethoxycarbonyl-BODIPY. …

Electrolyte Synthesis And Engineering For Alkali Metal Batteries, Yiwen Zhang

Dartmouth College Ph.D Dissertations

Batteries have been in increasing demand over the last decade for portable electronic devices, electric vehicles, and grid-scale energy storage systems. While the electrode materials define the characteristic features of a battery system, the composition of the electrolyte is of critical importance and needs to be engineered for different battery systems to ensure superior electrochemical performance. In this thesis, the basic functionality and fundamental mechanism of the electrolytes in battery systems are first introduced. Then, three major electrolyte engineering strategies are demonstrated, including electrolyte composition formulation, electrolyte-electrode component modification, and function-oriented electrolyte design. Firstly, the low-temperature capacity restraint of lithium …

Structural, Thermal, Optical, And Mechanical Properties Of Composite Films Developed From The Button Mushroom (Agaricus Bisporus)-Sourced High Molecular Weight Chitosan And Potato Starch, Buliyaminu A. Alimi, Monjural Hoque, Shivani Pathania, Jude Wilson, Brendan Duffy, Jesus Maria Frias

Articles

Films were fabricated using the button mushroom (Agaricus bisporus) sourced high molecular weight chitosan with or without potato starch using the casting method. Glycerol was used as the plasticizer. Chitosan content in the film-forming solution (FFS) was varied (0.5, 0.75 and 1.0% w/v of FFS) while potato starch (1.0% of FFS) and glycerol (25% of the total solid content in the solution) contents were not varied. The control sample contained only chitosan (1.0% of the FFS) and glycerol. The effect of increasing the content of chitosan on the rheological properties of FFS and the properties of the films were investigated. …

Silica Particles Convert Thiol-Containing Molecules To Disulfides, Yangjie Li, Kurt W. Kolasinski, Richard N. Zare

Chemistry Faculty Publications

Synthetic amorphous silica is a common food additive and a popular cosmetic ingredient. Mesoporous silica particles are also widely studied for their potential use in drug delivery and imaging applications because of their unique properties, such as tunable pore sizes, large surfaces areas, and assumed biocompatibility. Such a nanomaterial, when consisting of pure silicon dioxide, is generally considered to be chemically inert, but in this study, we showed that oxidation yields for different compounds were facilitated by simply incubating aqueous solutions with pure silica particles. Three thiol-containing molecules, L-cysteine, glutathione, and D-penicillamine, were studied separately, and it was found that …

Exploration And Synthesis Of Half-Heusler And Disordered Ternary Intermetallic Single Crystals, Md Fahel Bin Noor

Graduate Theses/Dissertations

Due to their distinct physical and chemical characteristics, half-Heusler compounds are intermetallic materials that have undergone substantial research. The general formula for these compounds is XYZ, where X and Y are transition metals and Z is a p-block element. Thermoelectricity is among the half-Heusler compounds' most exciting potential uses, but additional possible applications include spintronics, magnetic refrigeration, and superconductivity, among others. Recently, half-Heuslers (and Heuslers) have emerged as candidates for catalysts for hydrogenation. The CoNbSn half-Heusler compound, as well as another unique intermetallic ternary compound, the disordered Mn_4-xCr_xAl₁₁, were successfully grown as single crystals …

Solid State Nmr Analysis Of Insect Wing Membranes, Samuel Eddy

Graduate Theses, Dissertations, and Problem Reports (ETD)

Solid State NMR is a powerful tool for analyzing the chemical composition of insects. Previous studies have used Solid State NMR to investigate the chemical composition and investigate the sclerotization (tanning) process of insect exoskeletons. Acquiring sufficient exoskeleton sample for analysis has been relatively simple. This is however not the case for other components of an insect’s physiology, particularly the wing membrane material. The wings of an insect only compose a small percentage of their overall body mass, and many hundreds to thousands of insects must be processed in order to achieve a few milligrams of wing membrane sample. The …

Synthesis And Self-Assembling Properties Of Carbohydrate- And Diarylethene-Based Photoswitchable Molecular Gelators, Pramod Aryal, Joedian Morris, Surya B. Adhikari, Jonathan Bietsch, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low-molecular-weight gelators are interesting new materials with many potential applications. These compounds can be designed to include multiple stimuli-responsive functional groups. In this study, we designed and synthesized several chemically responsive bola-glycolipids and dimeric carbohydrate- and diarylethene-based photoswitchable derivatives. The dimeric glycolipids formed stable gels in a variety of solvent systems. The best performing gelators in this series contained decanedioic and dithienylethene (DTE) spacers, which formed gels in eight and nine of the tested solvents, respectively. The two new DTE-containing esters possessed interesting photoswitching properties and DTE derivative 7 was found to have versatile gelation properties in many solvents, …

Synthesis Of A Series Of Trimeric Branched Glycoconjugates And Their Applications For Supramolecular Gels And Catalysis, Jonathan Bietsch, Anji Chen, Dan Wang, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-derived molecular gelators have found many practical applications as soft materials. To better understand the structure and molecular gelation relationship and further explore the applications of sugar-based gelators, we designed and synthesized eight trimeric branched sugar triazole derivatives and studied their self-assembling properties. These included glucose, glucosamine, galactose, and maltose derivatives. Interestingly, the gelation properties of these compounds exhibited correlations with the peripheral sugar structures. The maltose derivative did not form gels in the tested solvents, but all other compounds exhibited gelation properties in at least one of the solvents. Glucose derivatives showed superior performance, followed by glucosamine derivatives. They …

Computational Investigation Of The Ionization Potential Of Lead Sulfide Quantum Dots, Jessica Beyer

Scripps Senior Theses

The purpose of this work was to determine the impact of quantum dot size on ionization potential and to determine how the presence of carbonyl-based ligands affect the ionization potential of lead sulfide quantum dot systems. Ionization potential (IP) is defined as the energy required to remove an electron from an atom, molecule, or material. IP helps scientists determine how reactive the material of interest is, which is crucial information when manufacturing nanomaterials. Accurate quantum chemical calculations of ionization potential are challenging due to the computational cost associated with the numerical solution of the Dyson equation. In this work, the …