Tin Dioxide-Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Wilinger, Nicola Donato, Giovanni Neri, Nicola Pinna
Carbon materials such as carbon nanotubes (CNTs), graphene, and reduced graphene oxide (RGO) exhibit unique electrical properties, which are also influenced by the surrounding atmosphere. They are therefore promising sensing materials. Despite the existence of studies reporting the gas-sensing properties of metal oxide (MOx) coated nanostructured carbon, an incomplete understanding of their sensing mechanism remains. Here we report a systematic study on the preparation, characterization, and sensing properties of CNT and RGO composites with SnO2 coating. Atomic layer deposition (ALD) was applied to the conformal coating of the inner and outer walls of CNTs with thin films of SnO2 of ...
Evaluation Of A Filtration Sorbent For Remediation Of Arsenic In Groundwater, 2017 California State University - San Bernardino
Evaluation Of A Filtration Sorbent For Remediation Of Arsenic In Groundwater, Clement Do
Electronic Theses, Projects, and Dissertations
A commercially available product, PURA PhosLock, was identified and evaluated for use as a sorbent to remove dissolved arsenic (As) from drinking water. Although marketed as a product to remove phosphate in aquaria, it is composed of iron oxide hydroxide (i.e., FeO(OH)), which is also known to adsorb dissolved As species from water. Arsenic was measured using standard methods and Graphite Furnace Atomic Absorption Spectroscopy. A first rough filtration test was performed to see if the PhosLock adsorbed As well. About 50 g of PhosLock was used to filter 10 L of tap water containing 100 ppb As ...
Design And Fabrication Of Nanostructures For The Enhancement Of Photovoltaic Devices, 2017 University of New Orleans
Design And Fabrication Of Nanostructures For The Enhancement Of Photovoltaic Devices, Richard M. Prevost Iii
University of New Orleans Theses and Dissertations
In 2012 the net world electricity generation was 21.56 trillion kilowatt hours. Photovoltaics only accounted for only 0.1 trillion kilowatt hours, less than 1 % of the total power. Recently there has been a push to convert more energy production to renewable sources. In recent years a great deal of interest has been shown for dye sensitized solar cells. These devices use inexpensive materials and have reported efficiencies approaching 12% in the lab. Here methods have been studied to improve upon these, and other, devices. Different approaches for the addition of gold nanoparticles to TiO2 films were studied ...
Oxidative C-C Bond Formation Reactivity Of High Valent Nickel And Palladium Complexes, 2017 Washington University in St. Louis
Oxidative C-C Bond Formation Reactivity Of High Valent Nickel And Palladium Complexes, Michael Benjamin Watson
Arts & Sciences Electronic Theses and Dissertations
The development of both palladium and nickel catalysis over the past several decades has led to the ability to perform a multitude of C-C coupling, C-Heteroatom coupling, and C-H functionalization reactions. These reactions typically utilize a catalytic cycle involving Pd0/II/IV and Ni0/II. While using these types of catalytic cycles one can create a multitude of different hard to make bonds, it is always important to keep expanding what we view as potential catalytic intermediates to keep developing new cycles capable of new transformations. One such way to expand our knowledge of these catalytic cycles is to look ...
Reactions Of Nitric Oxide With Beta-Hydroxylimino Esters, 2017 University of Wyoming
Reactions Of Nitric Oxide With Beta-Hydroxylimino Esters, Elayna M. Mahone
Honors Theses AY 16/17
Nitric oxide (NO) and its one electron reduction product nitroxyl (HNO) are known to act as vasodilators in mammals, including humans, and are considered a possible cure to cardiovascular diseases. However, their instability and high reactivity with atmospheric oxygen preclude the direct use of them as drugs. Recent work has shown that NO donor molecules can be used as pro-drugs to deliver NO to the appropriate bio-sites. Therefore, there is considerable research interest in the synthesis and studies of donors capable of releasing either of the molecules under physiological conditions.As part of our research effort towards the synthesis of ...
Functionalized Silica Gel For Adsorption Of Cesium From Solution, 2017 East Tennessee State University
Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii
Electronic Theses and Dissertations
Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of ...
An Electrochemical Characterization Of A Vanadium-Based Deoxydehydration Catalyst, 2017 University of Arkansas, Fayetteville
An Electrochemical Characterization Of A Vanadium-Based Deoxydehydration Catalyst, Joel Eric Baker
Theses and Dissertations
Alternative methods for the conversion of polyols into olefins, be it for carbon storage or hydrocarbon fuel production, have become prevalent in today’s chemical industry. One process in particular, deoxydehydration (DODH) has been proven effective in taking sustainable biomass derivatives and converting them through the utilization of various homogenous metal catalysts. While this process may show productive yields and material conversion, it is hindered by the need of a sacrificial reductant. This makes a novel process economically unviable and relatively unused outside of scientific research. That fact begs the question: Can the process be improved? It is proposed here ...
Controlled Synthesis And Utilization Of Metal And Oxide Hybrid Nanoparticles, 2017 University of Arkansas, Fayetteville
Controlled Synthesis And Utilization Of Metal And Oxide Hybrid Nanoparticles, Cameron Cowgur Crane
Theses and Dissertations
This dissertation reports the development of synthetic methods concerning rationally-designed, hybrid, and multifunctional nanomaterials. These methods are based on a wet chemical, solution phase approach that utilizes the knowledge of synthetic organic and inorganic chemistry to generate building blocks in solution for the growth of nanocrystals and hybrid nanostructures. This work builds on the prior knowledge of shape-controlled synthesis of noble metal nanocrystals and expands into the challenging realm of the more reactive first row transition metals. Specifically, a microemulsion sol-gel method was developed to synthesize Au-SiO2 dimers as precursors for the synthesis of segmented heterostructures of noble metals that ...
Structural Comparison Of Copper(Ii) Thiocyanate Pyridine Complexes, 2017 College of WIlliam & Mary
Structural Comparison Of Copper(Ii) Thiocyanate Pyridine Complexes, Joseph V. Handy
Undergraduate Honors Theses
Twenty-one novel complexes of copper(II) thiocyanate pyridine were synthesized in methanol from the source material Cu(NO3)2•2.5H2O and a diverse series of substituted pyridines (XPy). These complexes typically formed according to the formula trans-[Cu(NCS)2(XPy)2], with square-planar geometries that exhibited thiocyanate bridging via long Cu–S bonds. The length of this long bridging bond appears to loosely correlate to the substitution position of the pyridine ligand used, and resulted in square planar molecules forming edge-sharing chain networks of Jahn-Teller distorted octahedra. Several other structural types were also observed, resulting ...
Metalation And Structural Properties Of Apo-Metallothioneins, 2017 The University of Western Ontario
Metalation And Structural Properties Of Apo-Metallothioneins, Gordon W. Irvine
Electronic Thesis and Dissertation Repository
Metals are required by a quarter of all proteins to achieve their biological function, whether in an active site involved in catalytic chemistry or in a structural capacity. Metals are tightly regulated at the cellular level due to their propensity to cause unwanted side reactions and to be scavenged for use by pathogens. One of the proteins involved in this regulation of metal homeostasis is metallothionein (MT) which is a small, cysteine rich protein primarily involved in the regulation of zinc and copper homeostasis and heavy metal detoxification. MT is unique in its high cysteine content (~30% of the residues ...
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, 2017 University of Kentucky
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali, Marcelo I. Guzman
Chemistry Faculty Publications
How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence ...
Effects Of Binding Affinity Between Bovine Serum Albumin And Platinum Drugs, 2017 Western Kentucky University
Effects Of Binding Affinity Between Bovine Serum Albumin And Platinum Drugs, Nathan Puckett
Masters Theses & Specialist Projects
Platinum complex drugs such as cisplatin have been used as highly successful chemotherapy drugs since the 1970s. We are interested in how the ligands attached to cisplatin analogs influences their reactivity with biologically relevant targets along with time and amount. For this study, reactions were conducted to determine the reactivity between different platinum compounds and the protein bovine serum albumin. Various platinum compounds with different ligands were reacted in varying amounts with albumin in ammonium acetate buffer for either 1 hour, 4 hours, or 24 hours. Each reaction was quenched after the designated reaction time by dialysis and the platinum ...
The Effects Of Carrier Ligands On Cisplatin Binding To Cysteine And Methionine, 2017 Western Kentucky University
The Effects Of Carrier Ligands On Cisplatin Binding To Cysteine And Methionine, Adam C.R Smith
Masters Theses & Specialist Projects
We have reacted several derivatives of the anticancer drug cisplatin with N-acetyl-Lcysteine (N-AcCys) and N-acetyl-L-methionine (N-AcMet), which are two of the primary amino acid targets of platinum. NMR spectroscopy was used to monitor the reactions and determine the effect the different ligands would have on the platinum reactivity. Several of the platinum compounds were tested at pH of 4 and 7, and with platinum:amino acid ratios of 1:1, 2:1 and 1:2. Competition reactions between cysteine and methionine were done to confirm which would react with the platinum compound first. [Pt(dien)(NO3)]+ reacts faster with methionine ...
Synthesis, Kinetic And Catalytic Studies Of Manganese Complexes With Corrole And Porphyrin Ligands, 2017 Western Kentucky University
Synthesis, Kinetic And Catalytic Studies Of Manganese Complexes With Corrole And Porphyrin Ligands, Haleh Jeddi
Masters Theses & Specialist Projects
High-valent transition metal-oxo intermediates play a significant role in the catalytic cycle of the ubiquitous cytochrome P450 enzymes and in biomimetic catalytic systems. In this work, manganese(III) porphyrin and corrole systems (2) were synthesized and characterized by UV-vis absorbance and 1H-NMR, matching literaturereported spectroscopic data. Manganese(V)-oxo corroles (3) and a manganese(IV)-oxo porphyrin (4) were successfully generated by chemical oxidation using mchloroperoxybenzoic acid (m-CPBA), and their oxidation reactions with organic reductants were comparatively investigated. Results from single-turnover kinetic studies indicate that in the tris(pentafluorophenyl)corrole system (3a), the active oxidizing intermediate differs in different solvents ...
Two Homologous Intermetallic Phases In The Na–Au–Zn System With Sodium Bound In Unusual Paired Sites Within 1d Tunnels, Saroj L. Samal, Qisheng Lin, John D. Corbett
The Na–Au–Zn system contains the two intermetallic phases Na0.97(4)Au2Zn4 (I) and Na0.72(4)Au2Zn2 (II) that are commensurately and incommensurately modulated derivatives of K0.37Cd2, respectively. Compound I crystallizes in tetragonal space group P4/mbm (No. 127), a = 7.986(1) Å, c = 7.971(1) Å, Z = 4, as a 1 × 1 × 3 superstructure derivative of K0.37Cd2 (I4/mcm). Compound II is a weakly incommensurate derivative of K0.37Cd2 with a modulation vector q = 0.189(1) along c. Its structure was solved in superspace group P4/mbm(00g)00ss, a = 7 ...
Tuning Complexity By Lithiation: A Family Of Intergrowth Structures Using Condensed Hypho-Icosahedra In The Li-Doped Ca–Zn System, Qisheng Lin, Ran Zhu, Gordon J. Miller
Cluster chemistry of intermetallics with valence electron counts (VECs) in the range of 2.0–3.0 is intriguing. Lithiation of polar intermetallics in this VEC region is found to be an effective chemical route to produce new complex structures with different stability mechanisms. In this work, two new complex intermetallic structures have been discovered in the Ca–Li–Zn system: Ca12LixZn59–xand Ca15LixZn75–x. Ca12LixZn59–x, x ≈ 5.65(3)–14.95(3), forms in the trigonal space group R3̅m, with a = 9.074(1)–9.1699(2) Å, c ...
Mg35cu24ga53: A Three-Dimensional Cubic Network Composed Of Interconnected Cu6ga6 Icosahedra, Mg-Centered Ga16 Icosioctahedra, And A Magnesium Lattice, Qisheng Lin, John D. Corbett
Single-crystal X-ray structural determinations for the Mg35.12(4)Cu24Ga53.58(6) and Mg35.6(4)Cu24Ga52.66(6) refined compositions (Fd3̄m, Z = 4) reveal empty (Cu,Ga)12 icosahedra and centered MgGa16 icosioctahedra that are interconnected at every vertex to a compact three-dimensional anion network. A small range of variable occupancy exists on one of three Ga and one of four Mg positions. The clusters are well-bonded and held in different sized cavities, in which they are also directly bonded to a Mg cation network. The two networks thus interpenetrate each other, and there are no spacers. The ...
Synthesis, Structure, And Bonding Of Sc4mgxcu15-Xga~7.5 (X = 0, 0.5): Two Incommensurately Modulated Scandium Substitution Derivatives Of Cubic Mg2cu6ga5, Qisheng Lin, Sven Lidin, John D. Corbett
The substitution of scandium for magnesium in Mg2Cu6Ga5 (Mg2Zn11-type) yields an irrational superstructure phase that includes the refined compositions, Sc4Mg0.50(2)Cu14.50(2)Ga7.61(2) and Sc4Cu14.76(2)Ga7.51(2). These crystallize in Cmmm, a = ∼8.31 Å, b = ∼21.72 Å, c = ∼8.30 Å. The structures feature Sc2 dimers, Cu6 octahedra, a 3D CuGa (Cu12Ga2) framework, and arachno gallium-centered Cu4Ga6 icosahedra that are condensed into zigzag chains. The arrangement of these building blocks exhibits a topologic relationship to Mg2Cu6Ga5. Further studies reveal that the quaternary compound exhibits incommensurate modulations along a, with q ...
Lithiation-Induced Zinc Clustering Of Zn3, Zn12, And Zn18 Units In Zintl-Like Ca∼ 30li3+ Xzn60–X (X= 0.44–1.38), Qisheng Lin
Zinc clusters are not common for binary intermetallics with relatively low zinc content, but this work shows that zinc clustering can be triggered by lithiation, as exemplified by Ca∼30Li3+xZn60–x, P6/mmm, Z = 1, which can be directly converted from CaZn2. Two end members of the solid solution (x = 0.44 and 1.38) were established and structurally characterized by single-crystal X-ray diffraction analyses: Ca30Li3.44(6)Zn59.56(6), a = 15.4651(9) Å, c = 9.3898(3) Å; Ca30.45(2)Li4.38(6)Zn58.62(6), a = 15.524(3) Å, c = 9.413(2 ...
M3(Au,Ge)19 And M3.25(Au,Ge)18 (M = Ca, Yb): Distinctive Phase Separations Driven By Configurational Disorder In Cubic Ycd6-Type Derivatives, Qisheng Lin, John D. Corbett
Exploratory syntheses in the M−Au−Ge (M = Ca, Yb) systems have led to the discovery of two cleanly separated non-stoichiometric phases M3Au∼14.4Ge∼4.6 (I) and M3.25Au∼12.7Ge∼5.3 (II). Single crystal X-ray studies reveal that both (space group Im3̅) feature body-centered-cubic packing of five-shell multiply endohedral clusters that resemble those in the parent YCd6 (= Y3Cd18) and are akin to approximate phases in other quasicrystal systems. However, differences resulting from various disorders in these are distinctive. The innermost cluster in the M3Au∼14.4Ge∼4.6 phase (I) remains a disordered tetrahedron, as ...