Materials Chemistry Commons^™

Novel Thiophene Supported N,N'-Chelating Ligands And Their Main Group Compounds, Jacquelyn T. Price

University of Western Ontario - Electronic Thesis and Dissertation Repository

Main group chemistry has advanced from studying fundamental curiosities, including low oxidation state, low-valent, p-block elements to tailoring these unique, reactive species for specific functional applications. This thesis examines the structure, bonding and reactivity of select group 13, 14 and 15 elements supported by N,N'-chelating ligands decorated with either thiophene, benzo[1,2-b:5,6-b']dithiophene or bis(2,5-dimethylthienyl)ethene substituents and allowing for subsequent reactivity and photophysical properties to be determined.

The synthesis of a new diamino ligand containing a thiophene ring in the backbone was used to support a 7-membered phosphenium cation. The 1:1 ...

N-Doped Multiwalled Carbon Nanotubes: Functionalization, Characterization And Application In Li Ion Batteries, Aman Preet Kaur

Theses and Dissertations--Chemistry

The focus of this dissertation is to utilize chemical functionalization as a probe to investigate the reactivity of N-doped multiwalled carbon nanotubes (N-MWCNTs). The surface of N-MWCNTs, being a set of potentially reactive graphene edges, provides a large number of reactive sites for chemical modification, so considerable changes in chemical and physical properties can be envisaged. We observed that both reduction (dissolving metal reduction/alkylation) and oxidation (H₂SO₄/HNO₃ and H₂SO₄/KMnO₄ mixtures) of N-MWCNTs lead to formation of interesting spiral channels and spiraled carbon nanoribbons. A variety of techniques, including TGA ...

An Investigation Into The Sustainability Of Advanced Materials And Systems As Energy Sources In Commuter Transportation, Austin Alan Albert

Chemistry Publications and Other Works

Modern society depends on cheap and plentiful sources of energy. For most of the 20th century, fossil fuel in the form of coal, natural gas, and petroleum have been this energy source. The majority of petroleum in the U.S. goes in to fueling the light duty transportation fleet. However, we know that coal, natural gas, and crude oil have an expiration date, and we have recently learned that their use has caused and is still causing severe damage to the earth’s atmosphere. With these reasons in mind, new sources of inexpensive and abundant energy must be found, which ...

Complex Rare-Earth Antimonide Suboxides For Thermoelectric Applications, Peng Li Wang

Open Access Dissertations and Theses

Thermoelectric (TE) materials are able to convert heat directly into electricity and vice versa. This special property makes them valuable for a variety of applications involving power generation and refrigeration. In the search for potential high-performance TE materials, a number of rare-earth (RE) antimonide suboxide phases have been investigated.This presentation will focus on two classes of rare-earth antimonide suboxides: the RE₃Sb₃O₃ and RE₈Sb_3-dO₈ phases (C2/m space group) based on the RE–O frameworks and the anti-ThCr₂Si₂ type RE₂SbO₂ compounds ...

Synthesis Of Palladium-Based Electrocatalysis—From Pure Metal To Bimetallic Nanoparticles, Haijun Gao

Masters Theses

This thesis focuses on synthesis and characterization of palladium-based nanoparticles. Background information of the research in this thesis is provided in Chapter 1. Preparation and characterization of pure palladium nanoparticles are presented in Chapter 2. A fast and convenient method to prepare ultra small Pd nanoparticles via Pluronic P123 reduction is discussed in detail. Impregnation method and poly method are also studied in this chapter. Chapter 3 reports the studies of these methods to prepare ultra small bimetallic (bimetallic means a mixture of two metals) palladium-based nanoparticles. Oleylamine-mediated method used Pd nanoparticles prepared via P123 reduction as precursor. Ultra small ...

Synthesis And Functionalization Of Small Silver Nanoparticles, Chris Menter, Jeunghoon Lee, Sarah Rhen, Elton Graugnard, Bernard Yurke, William Knowlton, Will Hughes, Wan Kuang

College of Arts and Sciences Poster Presentations

Metal nanoparticles in general exhibit interesting properties due to their small sizes. This response shows up as an intense absorption band in the visible region making metallic nanoparticles ideal probes for medical imaging as well as for countless other applications. Functionalizing metallic nanoparticles with DNA enables targeted labeling, controlled by their base sequence. Another purpose of functionalization is to attach the nanoparticle to a DNA substrate allowing controlled bottom up engineering of nanoscale devices. Gold or gold-encapsulated silver is usually used for these purposes instead of bare silver due to the ease with which silver is oxidized although silver nanoparticles ...

A Highly Efficient Tio2-Xcx Nano-Heterojunction Photocatalyst For Visible-Light Induced Antibacterial Applications, Vinodkumar Etacheri, Michael Seery, Stephen Hinder, Georg Michlits, Suresh C. Pillai

Articles

Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0 ...

Novel Microwave Assisted Synthesis Of Zns Nanomaterials, Suresh Pillai, Michael Seery, Damian W. Synnott, John Colreavy, Stephen Hinder

Articles

A novel ambient pressure microwave-assisted technique is developed in which silver and indium modified ZnS is synthesised. The as prepared ZnS is characterised by X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and luminescence spectroscopy. This procedure produced crystalline materials with particle sizes below 10 nm. The synthesis technique leads to defects in the crystal which induce mid energy levels in the band gap and lead to indoor light photocatalytic activity. Increasing the amount of silver causes a phase transition from cubic blende to hexagonal phase ZnS. In a comparative study, when the ZnS cubic blende is heated in a conventional ...

Efficient Electrochemical Functionalization Of Carbon Nanotubes And Carbon Nanotube Membranes For Energy, Drug Delivery And Potential Catalysis Applications, Xin Zhan

Theses and Dissertations--Chemistry

Electrochemical diazonium grafting offers versatile functionalization of chemically inert graphite under mild condition, which is particularly suitable for CNT composite modification. Tetrafluorinated carboxylphenyl diazonium grafting provides the most controllable functionalization chemistry allowing near monolayer levels of functionality on carbon nanotubes. The functional density was successfully quantified by anion selective dye-assay and X-ray photoelectron spectroscopy (XPS) of thiol-Au self-assembled monolayers (SAM) as a calibration reference. This technique enables monolayer functionality at the tips of carbon nanotube membranes for biomimetic pumps and valves as well as thin conductive layers for CNT-based high area electrochemical support electrodes.

Double-walled carbon nanotube (DWCNT) membranes were ...

The Bench Synthesis Of Silver Nanostructures Of Variable Size And An Introductory Analysis Of Their Optical Properties, Aoife Power, Anthony J. Betts, John F. Cassidy

Articles

A laboratory practical was designed for use by both undergraduate and second level students to demonstrate the synthesis and characterisation of tuneable silver colloids. It clearly illustrates the novel optical properties of silver nanoparticles compared to the bulk metal. The synthesis is both rapid and repeatable, and can be conducted on the laboratory bench at room temperature.

Synthesis And Temperature-Induced Phase Transfer Behavior Of Thermosensitive Hairy Particles Between Aqueous Solution And A Hydrophobic Ionic Liquid, Jonathan Michael Horton

Chemistry Publications and Other Works

Chapter 1 describes the synthesis and phase transfer behavior of a series of 205 nm silica particles grafted with thermosensitive polymers of methoxyoligo(ethylene glycol) methacrylates. The hairy particles with sufficiently high lower critical solution temperatures underwent reversible and quantitative transfer between water and [EMIM][TFSA] in response to temperature changes. The transfer temperature (T_tr) of hairy particles from water to [EMIM][TFSA] upon heating was a linear function of the cloud point (CP) of corresponding free polymer in [EMIM][TFSA]-saturated water. Chapter 2 presents the synthesis and study of thermo- and pH-sensitive hairy particles. A small amount ...

A Study Of Gamma Radiation Induced Carbon Steel Corrosion, Kevin Daub

Electronic Thesis and Dissertation Repository

This thesis presents work on the development of a mechanistic understanding of the effect of ionizing radiation on the aqueous corrosion kinetics of carbon steel. Exposed to ionizing radiation, water decomposes into a range of oxidizing (O₂, •OH, HO₂•, H₂O₂) to reducing (•e_aq^–, •O₂^–, •H) species. The production of the redox active species by radiolysis can have a significant effect on the corrosion behaviour of a metal. Of particular interest is the effect of radiolysis on corrosion when the solution environment, such as temperature, pH, and concentrations of chemical additives, changes over time ...

Lithium Mas Nmr Studies Of Lithium Ion Environment And Ion Dynamic Process In Lithium Iron And Magnesium Pyrophosphate As New Series Of Cathode Materials For Lithium Ion Batteries, Xuan He

Open Access Dissertations and Theses

Lithium-ion batteries provide a more cost-effective and non-toxic source of reusable energy compare to other energy sources. Several research studies have lead to production of some more promising cathode components for lithium ion batteries. Recently, a new series of pyrophosphate-based composition Li₂FeP₂O₇ and Li₂MnP₂O₇ has been reported as cathode materials. They have shown a 3D framework structure and the two Lithium-ions in the three-dimensional tunnel structure make it possible that more than one lithium ion be extracted during cycling. Lithium solid state nuclear magnetic resonance (NMR) is an effective technique ...

In Situ Measurements Of Electron-Beam-Induced Surface Voltage Of Highly Resistive Materials, Joshua Hodges

All Graduate Theses and Dissertations

This study presents the development, calibration, characterization, and use of new instrumentation for in situ measurements of electron-beam-induced surface voltage. The instrument capabilities allow for measurements of a full range of insulating materials that are of concern to NASA spacecraft charging experts. These measurements are made using moveable capacitive sensor electrodes that can be swept across the sample using an in vacu stepper motor. Testing has shown a voltage range of more than ±30 kV with a low-voltage resolution of 0.2 V. The movable sensors allow for a radial measurement of surface voltage with spatial resolution as low as ...

Synthesis And Characterization Of Functionalized Nanomaterials: Heterogeneous Palladium Catalyst And Lithium-Doped Graphene Oxide, Benjamin E Estes

Doctoral Dissertations

As the Earth's population increases and natural resources decrease in supply, the development of new methods for energy storage and the efficient production of industrial chemicals becomes ever more important to humanity. The development of new nanomaterials may offer technological advances in the fields of sustainable energy production and storage, chemical production, medicine, and many others. The emerging field of nanoscience blends chemistry, physics, and engineering to create new materials that take advantage of properties found only on the nanoscale.

In this work, mesoporous silica spheres are used as a support for nanoparticles of palladium. This nanomaterial is shown ...

The Synthesis And Characterization Of Novel Group 13 Nanostructured Building Block Heterogeneous Silicate Catalysts, Joshua G. Abbott

Doctoral Dissertations

A building block approach and sequential addition methodology were utilized to prepare heterogeneous silicate catalysts containing atomically dispersed group 13 metal (B, Al, Ga) centers. The octa(trimethyltin) silsequioxane, Si8[sub]O12[sub](OSnMe3[sub])8[sub], was used as the building block for the synthesis of these materials. Reaction of the building block with a variety of group 13 metal chlorides led to the formation of cross-linked matrices. All prepared materials were characterized by gravimetric analysis, gas absorption, IR, and NMR. In addition, aluminum and boron samples where characterized by 27[sup]Al and 11[sup]B solid state ...

Studies On Molecular Sieve Crystallization And Heteroatomic Substitution, Adam R. Macintosh

Electronic Thesis and Dissertation Repository

Molecular sieves have been scientifically and industrially important materials since their inception. These porous, crystalline networks of tetrahedrally coordinated atoms bridged by oxygen are known for their extremely high surface area and low density, making them excellent systems for catalysis. The framework of the AlPO₄ family of molecular sieves is itself non-catalytic, but through heteroatomic substitution these materials can diversify into the catalytically active silicoaluminophosphate (SAPO) and metalloaluminophosphate (MAPO) families of heterogeneous acid and redox catalysts. Research into the methods by which these substitutions occur, and the effects therein on the crystallization of the sieves, is of great importance ...

Understanding Magnetosome Formation And Organization Using Scanning Transmission X-Ray Microscopy – X-Ray Magnetic Circular Dichroism, Samanbir Kalirai

Open Access Dissertations and Theses

Magnetotactic bacteria (MTB) are ubiquitous, multi-phylogenetic bacteria that actively synthesize chains of magnetic, membrane bound; single domain magnetite (Fe₃O₄) or greigite (Fe₃S₄) crystals, termed magnetosomes in order to better navigate to their preferred chemical environment using the Earth’s magnetic field. Discovered in 1963, the field is now focused on understanding magnetosome chain formation and associated processes through genetic studies as well as analytical techniques such as Transmission Electron Microscopy (TEM) and Scanning Transmission X-ray Microscopy – X-ray Magnetic Circular Dichroism (STXM-XMCD).

This thesis performed studies on Candidatus Magnetovibrio blakemorei strain MV-1 using STXM at ...

Understanding The Thermodynamic Behavior Of Nanoparticles To Tailor Polymer Nancomposite Structure, Mary Catherine Mutz

Doctoral Dissertations

The work presented in this dissertation is an attempt to understand the entropic and enthalpic forces that govern the dispersion and dissolution of nanoparticles in solutions and in thin polymer films with the end-goal of producing highly tailored products.

In the first part, neutron reflectivity was used to study the impact of nanoparticle presence on the surface segregation of deuterated polystyrene (dPS) in a polystyrene matrix. The impact of the presence of cylinders (carbon nanotubes), sheets (graphene), and spheres (polystyrene soft nanoparticles) on the surface segregation process and ultimate structure were examined. Experimental data indicate that the presence of the ...

Nonlinear Propagation Of Incoherent White Light In A Photopolymerisable Medium: From Single Self-Trapped Beams To 2-D And 3-D Lattices, Kailash Kasala

Open Access Dissertations and Theses

Optical beams that travel through a material without undergoing divergence are known as self-trapped beams. Self-trapping occurs when a beam induces a suitable index gradient in the medium that is capable of guiding the original beam. An incoherent light consists of femtosecond scale speckles, due to random phase fluctuations and were not thought to self-trap until recently. In 1997, Mitchell et al., showed that white light can self-trap, provided the medium cannot respond fast enough to form index gradients to these speckles individually. However, detailed studies have been hampered by a lack of suitable materials and strategies for enabling such ...