Rozprawy doktorskie: „Sulfides”

1

Jikei, Mitsutoshi. "Formation kinetics of polyarylene sulfides /". Electronic version of summary, 1993. http://www.wul.waseda.ac.jp/gakui/gaiyo/.pdf.

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Manolopoulos, Helen. "Metal sulfides in oxidizing freshwater systems /". *McMaster only, 2001.

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Ratmann, Cristiane Wienke Raubach. "Metal sulfides: photoluminescence and photocatalytic properties". Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/6279.

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Universidade Federal de Minas Gerais
In this work we report an experimental and theoretical study of photoluminescence (PL) and photocatalytic activity of pure metal sulfides and systems furnished prepared by microwave assisted solvothermal (MAS) method. The theoretical model of the decorated system was created in order to analyze the electronic transition, especially in their interfaces. The results show that the system interface decorated (core-shell) produces an electron charge transfer of holes from cadmium sulfide (CdS) to zinc sulfide (ZnS), which helps increase the PL and photocatalytic activity of the system. For the pure systems, was observed the efficacy of the method synthesis employed verified that the process for obtaining the ZnS and calcium sulfide (CaS) was extremely important. Through the theoretical models was possible to evaluate the influence caused by the solvothermal influence caused by the MAS method. The variation in the synthesis parameters shows a direct influence on the PL properties of sulfides obtained which can be attributed to structural organization. The theoretical results how this order and disorder of the system can affect these properties of the obtained materials.
Neste trabalho relata-se um estudo teórico e experimental da atividade fotoluminescente (FL) e fotocatalítica de sulfetos metálicos puros e em sistemas decorados preparados por intermédio do método solvotérmico assistido por micro-ondas. O modelo teórico do sistema decorado foi criado de forma a analisar a transição eletrônica, principalmente nas suas interfaces. Os resultados mostram que a interface do sistema decorado (core-shell) produz uma transferência de carga do elétron do sulfeto de cádmio (CdS) para os buracos do sulfeto de zinco (ZnS), o que ajuda a aumentar a atividade fotoluminescente e fotocatalítica do sistema. Para os sistemas puros, observou-se a eficácia do método de síntese empregado, sendo verificado que o processo de obtenção do ZnS e sulfeto de cálcio (CaS) foi de extrema importância. Por intermédio dos modelos teóricos foi possível avaliar a influência causada pelo método. A variação nos parâmetros de síntese mostra uma influência direta nas propriedades FL dos sulfetos obtidos que pode ser atribuída a organização estrutural. O modelo teórico mostra como essa ordem e desordem do sistema podem afetar essas propriedades dos materiais obtidos.

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4

Stani´c, Vesha. "Sol-gel processing of metal sulfides". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21641.pdf.

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Senior, James Daniel. "Atropisomerism in biaryl sulfides and sulfones". Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498670.

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The thesis describes research carried out on the synthesis and asymmetric synthesis of atropisomeric biaryl sulfides and sulfones. Chapter one describes synthetic strategies employed in the synthesis of biaryl sulfides and sulfones. A synthetic route that allowed the incorporation ortho substituents of various sizes and the effect of these substitution patterns on barriers to rotation is described. Research towards more direct routes to compounds with the required substitution pattern is then discussed. Having uncovered suitable substitution patterns to achieve atropisomerism in biaryl sulfides and sulfones chapter two goes on to describe methods attempted in the asymmetric synthesis of these compounds. The strategies described include asymmetric cross coupling, kinetic resolution and the use of sulfoxide auxiliaries for dynamic thermodynamic resolution of biaryl sulfones. The first example of an symmetric synthesis of an atropisomeric biaryl sulfone is reported. Chapter three outlines possible applications of biaryl sulfides and sulfones and the synthesis of bis-phosphines based on the biaryl sulfone background using methods described in chapter one.

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6

Stephens, Ifan Erfyl Lester. "Polysulfide electrocatalysis at transition metal sulfides". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608910.

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Ramasamy, Karthik. "New molecular precursors for metal sulfides". Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/new-molecular-precursors-for-metal-sulfides(49bcd8c0-4a37-4eb1-892e-7a7973f8f3cd).html.

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Metal sulfide thin films are important class of materials which have applications in photovoltaics, microelectronics and displays. Chemical vapour deposition (CVD) is well known method for the deposition of high quality thin films. Very few classes of single source precursors (eg: dithiocarbamates, xanthates) were successful for the deposition of good quality metal sulfide films by MOCVD. This limited choice was due to the difficulties of finding precursors with suitable physico-chemical properties. Hence, it is important to develop precursors with suitable volatility, solubility and being able to deposit films with little or no contamination. This work describes the synthesis of a series of metal (Fe, Co, Ni, Zn, Cd) complexes of thio- and dithio-biuret ligands, their structural and spectroscopic characterization and thermal decomposition. The complexes were used as single source precursors for the deposition of iron, cobalt, nickel, zinc, cadmium and zinc cadmium sulfide thin films by AACVD. The effect of alkyl groups, coordinating atoms, deposition temperatures on phases and morphology of the films were studied. The deposited films were characterised by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and atomic force microscopy (AFM). The complex [Fe(SON(CNiPr2)2)3] gave hexagonal troilite FeS films with small amount of tetragonal pyrrhotites Fe1-xS at 300 °C, whereas only troilite FeS was deposited at 350, 400 or 450 °C. Complexes [Fe2(µ-OMe)2 (SON(CNEt2)2)2] and [Fe(SON(CNEt2)2)3] deposited a mixture of hexagonal troilite FeS and cubic pyrite FeS2 films at all temperatures. [Fe(SON(CNMe2)2)3] deposited very thin films of FeS at all temperatures as troilite. Complexes [Co(N(SCNMe2)2)3] and [Co(N(SCNEt2)2)3] deposited hexagonal Co1-xS films at all temperatures of 350-500 °C, whereas [Co(SON(CNiPr2)2)2] gave mixture of cubic and hexagonal Co4S3 films at 280-400 °C. Thiobiuret complex [Ni(SON(CNMe2)2)2] gave orthorhombic Ni7S6. Complexes [Ni(SON(CNMe2CNEt2))2] and [Ni(SON(CNEt2)2)2] gave mixtures of hexagonal Ni17S18 and orthorhombic Ni7S6. In contrast, [Ni(SON(CNiPr2)2)2] gave orthorhombic Ni9S8. Dithiobiuret complexes [Ni(N(SCNMe2SCNEt2))2] and [Ni(N(SCNEt2)2)2] gave hexagonal NiS1.03 at 360 and 400 °C, orthorhombic Ni7S6 phase at 440 and 480 °C. The zinc complexes [Zn(N(SCNMe2)2)2] and [Zn(SON(CNiPr2)2)2] deposited cubic ZnS at 300 and 350 °C, whereas at 400 and 450 °C hexagonal ZnS were apparent [Zn(N(SCNEt2)2)2] gave hexagonal ZnS films at all deposition temperatures. Cadmium complexes [Cd(N(SCNMe2)2)2], [Cd(N(SCNEt2)2)2] and [Cd(SON(CNiPr2)2)2] gave hexagonal CdS films at all deposition temperatures.

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8

Eghbali, Nicolas Dara. "The chemistry of novel cyclic diesters : dialkoxy disulfide, thionosulfite and carbonate". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103380.

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The synthesis and chemistry of some new cyclic diesters were investigated. The first part of the thesis is concerned with the study of new cyclic diesters derived from thiosulfurous acid, namely cyclic dialkoxy disulfides and their structural thionosulfite isomers. The second part focuses on the development of a new methodology for the synthesis of cyclic carbonates (carbonic acid diesters).
The synthesis of new cyclic dialkoxy-disulfides is described in Chapter 3. Five new molecules have been synthesized and fully characterized. An X-ray structure was obtained for the 2,3-furandimethylene dialkoxy disulfide. The substrates were prepared in an attempt to rationalize some of the existing limitations of the synthetic methodology.
The relationship and possible interconversion between the newly prepared cyclic dialkoxy disulfides and their structural thionosulfite isomers were investigated. Benzene dimethanoate disulfide was successfully converted to its structural thionosulfite isomer under acidic conditions. Further investigations show the existence of a reversible sulfur extrusion process between thionosulfite and sulfoxylate. This sequential transformation brings the first chemical demonstration that branched bond sulfur can indeed be involved in sulfur extrusion as was first predicted by Foss in 1950.
Finally, a highly efficient method to convert alkenes and CO2 into cyclic carbonates directly in water is presented in the second part of the thesis. Using N-bromosuccinimide (NBS) together with 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU) in water, alkenes were converted into cyclic carbonates nearly quantitatively. Cyclic carbonates were also formed efficiently by using a catalytic amount of bromide ion together with aqueous hydrogen peroxide.

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9

Recatalá, Ferrandis David. "Photoactive Materials Based on Molybdenum Cluster Sulfides". Doctoral thesis, Universitat Jaume I, 2015. http://hdl.handle.net/10803/296561.

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Coordination Chemistry deals with the synthesis and study of the physicochemical properties of metal complexes. Cluster Chemistry is a subfield of Coordination Chemistry, which focuses on the functionalization of complexes in which two or more metal atoms are directly bonded. Over the past few years, Cluster Chemistry has attracted a growing interest among scientists from diverse areas, mainly due to the fascinating properties of these compounds. A historical evolution of the term cluster, as well as an outline of the role of coordinated ligands and structural types in the final properties of metal clusters are provided in Chapter 1.

This PhD Thesis is devoted to the synthesis, characterization and applications of two families of group VI metal clusters containing dithiolene or diimine ligands, as detailed in Chapter 2. The synthetic approaches employed for the preparation of a series of dinuclear M2Q2S2 cluster chalcogenides (M = Mo, W; Q = O, or S) bearing bifunctional dithiolene ligands are described in Chapter 3. These metal clusters present great potential for the design of heterometallic systems.

Chapter 4 is concerned with the preparation of an extensive family of mixed-ligand diimine-halide (or diimine-dithiolene) trinuclear molybdenum sulfides based on the Mo3S7 core. A great number of bipyridine and phenanthroline derivatives have been coordinated to these Mo3S7 units. The most important feature of the resulting cluster complexes of formula Mo3S7X4(diimine), where X = Cl, or Br, is their crystallization as [Mo3S7X4(diimine)·X]- aggregates, in which the sulfur axial atoms participate in non-bonding interactions with halide anions.

The physicochemical properties of both series of metal clusters mentioned above are explored in Chapters 5 and 6. The luminescence properties of bis(dithiolene) M2Q2S2 clusters (M = Mo, W; Q = O, or S), together with those of Mo3S7 clusters functionalized with imidazophenanthroline ligands are detailed in Chapter 5. These diimine Mo3S7 complexes exhibit luminescent anion sensing behavior. The optical limiting capabilities of both series of compounds, namely M2Q2S2- and Mo3S7-based clusters, are also described in Chapter 5 with the aim of finding correlations between molecular structures and third-order nonlinear optical functions.

Chapter 6 examines the electro- and photocatalytic activity of diimine Mo3S7 clusters immobilized on TiO2 nanoparticles toward the hydrogen evolution reaction. This study has been stimulated by the analogy between the structure of Mo3S7 and the catalytic active sites of MoS2 nanoparticles. The electrochemical properties of these TiO2 electrodes are assessed in two different media, that is, aqueous perchloric acid and sulfide-sulfite mixtures. The role of the diimine ligands in the adsorption process is also described in this Chapter.

All experimental procedures employed in this work, together with the characterization of all compounds are presented in Chapter 7. Finally, the general conclusions of this PhD Thesis are provided in Chapter 8.

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10

Zuo, Yong. "Nanostructured Metal Sulfides for Electrochemical Energy Conversion". Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/670925.

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Storing the fluctuating renewable energy into synthetic fuels or in batteries is meaningful due to the emerging energy crisis. In this thesis, four nanostructured catalysts based on two kinds of metal sulfides, namely Cu2S and SnS2, were produced and optimized to improve their performance towards three key electrochemical energy conversion processes, namely electrochemical oxygen evolution, photoelectrochemical water splitting and lithium-ion batteries. Chapter 1 presented a general introduction to explain the motivation of the thesis topic. In chapter 2, a metallic copper substrate was used as current collector and chemical template to produce Cu2S nanorod arrays for electrochemical oxygen evolution reaction (OER). Suitable characterization tools were applied to investigate the chemical, structural and morphological transformation in OER operation, during which the initial Cu2S nanorod arrays would perform as a “pre-catalyst” that in-situ changed to CuO nanowires. Notably, the Cu2S-derived CuO showed significant improved OER performance compared with that of CuO prepared by directly annealing a Cu(OH)2 precursor, in terms of both activity and stability. Thus obtained electrocatalyst can be ranked among the best Cu-based OER catalysts reported so far. To take advantage of the unlimited solar energy, an ultrathin SnS2 NPL with a suitable band gap around 2.2 eV was produced via a hot-injection solution-based process in chapter 3. The unsatisfied photoelectrochemical (PEC) performance of bare SnS2 motivated me to deposit Pt NPs on its surface as cocatalyst via in-situ reduction of a Pt salt. The resulting SnS2-Pt heterostructures with optimal Pt amount showed significant improvement (six fold) towards PEC water oxidation. Mott-Schottky analysis and PEC impedance spectroscopy (PEIS) were used to analyze in more detail the effect of Pt on the PEC performance. The optimal SnS2-Pt heterostructure presented acceptable performance towards PEC water splitting. However, it still suffered from a moderate stability due to the peel-off of the catalyst layer from the FTO surface. To solve this problem, in chapter 4 we detailed a simple, versatile and scalable amine/thiol- based molecular ink to grow nanostructured SnS2 layers directly on conductive substrates such as FTO, stainless steel and carbon cloth. Such layers on FTO were characterized by excellent photocurrent densities. The same strategy was used to produce SnS2-graphene composites, SnS2-xSex ternary coatings and even phase pure SnSe2 layers. Finally, the potential of this precursor ink to produce gram scale amounts of unsupported SnS2 was also investigated. Apart from the application as a photocatalyst, SnS2 can also be a promising anode material for Li-ion batteries (LIB). In chapter 5, nanostructured SnS2 with different morphologies produced in chapter 3 were tested as LIB anodes firstly to find that thin SnS2 NPLs provided the highest performance. Thereafter, a colloidal synthesis strategy to grow the same SnS2 NPLs within a matrix of porous g-C3N4 (CN) and graphite plates (GPs) was developed and the obtained materials were tested for LIB application. Such hierarchical SnS2/CN/GP composites using SnS2-NPL as active materials, porous CN to provide avenues for electrolyte diffusion and ease the volumetric expansion of SnS2, and GP as “highways” for charge transport displayed excellent rate capabilities (536.5 mAh g-1 at 2.0 A g-1) and an outstanding stability (~99.7 % retention after 400 cycles), which were partially associated with a high pseudocapacitance contribution (88.8 % at 1.0 mV s-1). The excellent electrochemical properties of these nanocomposites were ascribed to the synergy created between the three components. Overall, four nanostructured catalysts based on Cu2S and SnS2 were prepared, and proper optimizations/treatments were defined to improve their catalytic performance. The results shown in this thesis demonstrate the promising application of non-toxic, low cost metal sulfides in electrochemical energy conversion technologies.
En esta tesis, se produjeron y optimizaron cuatro catalizadores nanoestructurados basados en Cu2S y SnS2 para mejorar su rendimiento hacia la conversión de energía electroquímica. El Capítulo 1 presentó una introducción general para explicar la motivación del tema de tesis. En el capítulo 2, las matrices de las nanovarillas de Cu2S se sintetizaron in situ sobre un sustrato de cobre metálico para la reacción electroquímica de evolución de oxígeno (OER). Se aplicaron herramientas de caracterización adecuadas para investigar la transformación en la operación OER, durante la cual las matrices iniciales de las nanovarillas Cu2S in situ cambió a nanohilos de CuO. En particular, el CuO derivado de Cu2S mostró un rendimiento de OER significativamente mejor cuando comparado al de CuO preparado mediante el recocido. En el capítulo 3, se detalló un proceso basado en una solución de inyección en caliente para producir nanoplacas ultrafinas SnS2 (NPL). Posteriormente, se cultivóPt en su superficie mediante la reducción in situ de una sal de Pt. Posteriormente se probó el rendimiento fotoelectroquímico (PEC) de los fotoanodes hacia la oxidación del agua. Los fotoanodes de SnS2-Pt optimizados proporcionaron densidades de fotocorriente significativamente más altas que el SnS2 desnudo (seis veces). Se analizó el efecto de Pt. En el capítulo 4, se informó una tinta molecular simple para cultivar capas de SnS2 nanoestructuradas directamente sobre sustratos conductores. Tales capas nanoestructuradas en FTO se caracterizaron por excelentes densidades de fotocorriente. Se utilize la misma estrategia para producir compuestos de grafeno-SnS2, recubrimientos ternarios SnS2-xSex, capas de SnSe2 de fase pura e incluso polvo de SnS2 a gran escala. En el capítulo 5, el SnS2 nanoestructurado con diferentes morfologías se probaron como ánodos LIB en primer lugar para encontrar que los NPL de SnS2 delgados proporcionaban el mayor rendimiento. Posteriormente, se desarrolló una estrategia de síntesis coloidal para cultivar los mismos NPL de SnS2 dentro de una matriz de g-C3N4 (CN) poroso y placas de grafito (GP) y se probaron para la aplicación LIB. Tales compuestos jerárquicos SnS2/CN/GP mostraron excelentes propiedades electroquímicas, lo que se atribuye a la sinergia creada entre los tres componentes como se investigó.

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11

Grippa, Alexander. "Structural investigation of Nb-based layer sulfides". Doctoral thesis, Stockholm University, Department of Physical, Inorganic and Structural Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-177.

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In this work we have investigated the intercalation of electron-donors between NbS₂ slabs in Nb-based layer sulfides.

Two series of Sr substituted Nb-based misfit sulfides belonging to the 1.5Q/1H and 1Q/1H series of misfit layer compounds have been synthesised. For large lanthanides (Ln=La, Ce), only the 1Q/1H compounds formed whereas for smaller lanthanides and yttrium, both types of phases can be obtained. The crystal structure of misfit sulfide (Pr_0.55Sr_0.45S)_1.15NbS₂ has been refined using the composite approach. In the Q-slab, Pr-atoms are partly replaced by Sr with a random distribution over one cation position. The crystal structure of misfit sulfide [(Sm_1/3Sr_2/3S)_1.5]_1.15NbS₂ belonging to the 1.5Q/1H series have also been determined. The obtained results suggest a preferred occupancy of the cation positions in the slab where Sr atoms mainly occupy positions on the exterior of the slab while Sm atoms are in the center of the slab. The (La_1-xSr_xS)_1.15NbS₂ solid solution (0.1

An attempt to synthesize Sr_xNbS₂ (0.1≤x≤0.5) intercalates was made but single phases were not obtained and increasing the temperature from 1000^оС to 1100^оС leads to the decomposition of these intercalates. Single crystals of Sr_0.22Nb_1.05S₂ and Sr_0.23NbS₂ were found and their structures were determined. The structures belong to two different types of packings with statistical distribution of Sr between layers.

A new superconducting sulfide, "EuNb₂S₅", was investigated by ED and HREM and its structure model consisting of Nb₇S₁₄ and (Eu₃S₄)₂ slabs alternating along the c-axis is suggested. An attempt to suggest a model for the structure of "SrNb₂S₅" by means of X-ray single crystal diffraction was made. The proposed structure consists of two types of slabs: a Nb₇S₁₄ and a [Sr₆(NbS₄)₂S] slab with niobium in tetrahedral coordination. It is shown that "SrNb₂S₅" and "EuNb₂S₅" are have similar structures.

For the first time, single crystals of the complex sulfide BaNb_0.9S₃ have also been studied by means of X-ray single crystal diffraction. The single crystal refinement and EDX analysis showed the existence of cation vacancies at the niobium position. BaNb_0.9S₃ has also been studied by ED and no superstructure was found which implies that and the vacancies are statistically distributed.

No improvement of the magnetic properties of the studied compounds was observed in comparison to NbS₂.

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Grippa, Alexander Yu. "Structural investigation of Nb-based layer sulfides /". Stockholm : Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-177.

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Gammon, Jonathan J. "Chiral base-mediated desymmetrisation of phosphine sulfides". Thesis, University of York, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516645.

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Rees, David Alan. "Synthesis of alkaline earth transition metal sulfides". Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311775.

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Dinnage, Christopher Walker. "Molecular precursor routes to transition metal sulfides". Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252054.

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Lukashev, Pavel. "Crystal and Electronic Structure of Copper Sulfides". Case Western Reserve University School of Graduate Studies / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=case1164213394.

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Guo, Qin. "Synthesis and oxidation of vinyl stannyl sulfides". Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/187512.

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The alpha-tin effect in which a C-Sn bond adjacent to a thioether interacts with the sulfur 3p lone pair orbital was found in saturated thioethers and results in a lowering of the oxidation potentials of these compounds. From the electrochemical oxidation potentials found in this study the alpha-tin effect is also present in vinyl sulfides. The geometry of the compounds is the key factor in determining the overlap of the sulfur 3p lone pair orbital with the filled C-Sn bond which results in decreasing oxidation potentials. The change in oxidation potentials of disubstituted stannylated or silylated compounds, 3 to 8, is small (compared with phenyl vinyl sulfur the change is about 0.18 to 0.24 V). The change in oxidation potential increase, when the overlap of the sulfur 3p lone pair orbital with the filled C-Sn bond increases such as in compounds 13 to 21 (in these cases the oxidation potentials compared to phenyl vinyl sulfur change by 0.24 to 0.57 V). The bistin effect does not seem to be an important factor in decreasing the oxidation potential due to a possible interaction between the sulfur and the tin cis to the sulfur. Since most of the compounds studied have a phenyl group attached to sulfur, rotation about the C-S bond to the phenyl ring is expected to affect the oxidation potential, but this does not appear to be a crucial factor in the vinyl sulfide system. The solved x-ray structures provide important information in understanding the relationship between the conformation and overlap between the sulfur 3p lone pair orbital and the filled C-Sn bond.

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Cunningham, Sharron Anne. "Soluble lanthanide thiolate complexes". Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367207.

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Gilfillan, Joanne Criseyde. "The structure and microbiology of floating sulphide oxidising biofilms". Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1003962.

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Floating sulphur biofilms are observed as surface layers in numerous aquatic sulphide-rich environments, and apparently play an important role in the cycling of sulphur in its various oxidation states. In addition to the conversion of sulphide to sulphur and/or sulphate species, it has been suspected that subsequent reduction back to sulphide may occur within the floating sulphur biofi1m in organic-rich environments. The use of sulphur biofilms for the harvesting of elemental sulphur from wastewater treatment systems has also been suggested. There is, however, little documented information in the literature on the structure of floating sulphur biofilms, or the microbial species responsible for their occurrence. In this study, floating sulphur biofilms were generated in a continuous flow baflle reactor and their structure was examined using scanning electron microscopy. It was found that they occur as layered structures with morphologically distinct bacterial forms present in different layers of the biofilm. The biofilpl structure was also found to be dynamic, with structural changes observed as feed conditions were altered. An enriched culture derived from the biofi1m demonstrated rates of sulphide oxidation comparable to values reported in the literature for liquid culture systems. The microbiology of the biofi1m was studied using traditional plate culture techniques and analysis ofrRNA genes. Identification of plate culture isolates as representatives of the biofi1m community proved to be limited, leading to a PeR-based cloning approach. The majority of the organisms present in the sulphur biofi1m were classified as species in the genus ~eudomonas, and a number of other bacterial species whose sulphide oxidising capacity has been noted previously. Surprisingly, only 2% of the clone library consisted of Thiobacillus spp., and no sulphate reducing bacteria were identified in the biofilm at all. These results indicate that in organic sulphide-rich environments facultative chemolithoheterotrophic bacterial forms predominate in floating sulphur biofilms, and that the complete biological cycling of sulphur may not occur in these systems.

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Colbow, Kevin Michael. "Lithium intercalation in titanium based oxides and sulfides". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27860.

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The Li-Ti-S ternary system was investigated. The elements and/or compounds, such as lithium sulfide, titanium disulfide and titanium trisulfide, were combined at high temperature (typically 500-900°C). The synthesized compounds containing one or more phases were structurally characterized using x-ray powder diffraction. When Lix TiS₂, (0 ≤ x ≤ 1) was synthesized at elevated temperature, a new polytype, 3R-LixTiS₂, was found for some values of x. The regions of stability of the 3R polytype and the well known 1T polytype are presented. Lithium can be intercalated or de-intercalated from both polytypes at room temperature. Ambient temperature Li/3R-LixTiS₂ cells have higher average voltages than Li/1T-Li TiS₂, cells. The lithium spinel oxides are another class of materials receiving attention as cathode materials in lithium secondary batteries. LiTi₂0₄ is metallic, has the cubic spinel structure and reacts with one further lithium atom to form Li₂Ti₂0₄. The related spinel Li₄/₃Ti₅/₃⁰₄͵ which is electrically insulating, also reacts reversibly with one lithium atom. Both Li₂Ti₂0₄ and Li₄/₃Ti₅/₃⁰₄͵ cells cycle reversibly, but have subtle differences in their voltage profiles. The difference in cell behaviour was interpreted based on the band structure of Li₁˖xTi₂₋x⁰₄. The mixed spinels LiMnyTi₂₋y⁰₄ (0 ≤ y ≤ 2) were also investigated. These compounds were synthesized at high temperature but their performance as cathodes in lithium batteries was not encouraging.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

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21

Yükseker, Ömer Kardes. "A study of molecular- and meso- tin sulfides". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58763.pdf.

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Kaur, Rajvinder. "Non-hydrolytic Sol-gel Synthesis of Tin Sulfides". University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1404243055.

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Zhang, Yuan. "Prepartion of multi-metal sulfides for electrochemical supercapacitors". Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1I014.

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Ces dernières années, les supercondensateurs électrochimiques (SE), en tant que systèmes de stockage d'énergie respectueux de l'environnement, sont confrontés à plusieurs défis liés aux performances, à la fonctionnalité et à la durabilité des matériaux clés. Parmi les différents types de supercondensateurs électrochimiques, les supercondensateurs hybrides combinent des électrodes avec différents mécanismes de stockage. En particulier, la combinaison d’électrodes à double couche (EDLC) et de type batterie devrait offrir une performance électrochimique améliorée. En ce qui concerne les supercondensateurs hybrides à comportement EDLC // type batterie, il a été largement reconnu que les matériaux en carbone, en raison de leur excellente conductivité électrique, de leur stabilité électrochimique et de leur grande surface spécifique, sont les candidats les plus prometteurs pour les matériaux d'électrode avec un comportement de type EDLC. En ce qui concerne les matériaux d'électrodes ayant un comportement de type batterie, il a été prouvé qu'en raison des réactions de transfert de charge faradiques impliquées dans le processus électrochimique, les matériaux à base de métaux de transition ont la capacité de stocker beaucoup de l'énergie et sont des candidats prometteurs pour les matériaux d'électrodes avec un comportement de type batterie. Dans cette thèse, différents matériaux d'électrodes en carbone, tels que l'oxyde de graphène réduit (rGO), l'oxyde de graphène réduit poreux (PrGO) et le polyéthylène-dioxythiophène-Fe-900 (PF-9), ont été préparés par une méthode d'oxydation et de réduction chimiques. De plus, des matériaux d'électrodes composés de métaux de transition, tels que CoS / support carboné (rGO ou PF-9), ZnCoS, ZnS / Ni3S2 et Sb2S3 / CoS2 / CrOOH ont été synthétisés par co-précipitation chimique et méthode d'échange d'ions. Une variété de techniques différentes (MES, MET, DRX, XPS, ICP-AES, BET, Raman) ont été utilisées pour caractériser les propriétés physico-chimiques des matériaux d'électrodes ainsi préparés. Leur performance électrochimique est également évaluée dans une cellule à 3 électrodes. Enfin, des supercondensateurs hybrides ont été assemblés et leur performance électrochimique a été évaluée dans un système à deux électrodes
In recent years, electrochemical supercapacitors (ESs), as environmentally-friendly energy storage systems, are facing several challenges associated with the performance, functionality, and durability of key materials. Among different types of ESs, hybrid supercapacitors, the combination of electrodes with different energy storage mechanisms, especially the combination of electrochemical double layer capacitance (EDLC) and battery-type behavior, are expected to offer enhanced electrochemical performance. Concerning hybrid supercapacitors consisting of EDLC//battery-type electrode materials, carbonaceous materials, owing to their excellent electrical conductivity, electrochemical stability, and large specific surface area, are the most promising candidates for electrode materials with EDLC-type behavior. For electrode materials with battery-type behavior, owing to the faradaic charge transfer reactions involved in the electrochemical process, transition metal compounds can store plenty of energy and represent one of the most promising candidates for electrode materials with battery-type behavior. In this thesis, different carbonaceous materials, such as reduced graphene oxide (rGO), porous reduced graphene oxide (PrGO), and poly-ethylene dioxythiophene-Fe-900 (PF-9), are prepared through chemical oxidation and reduction methods. Moreover, transition metal compounds, such as CoS/carbonaceous support (rGO or PF-9), ZnCoS, ZnS/Ni3S2 and Sb2S3/CoS2/CrOOH, are synthesized via chemical co-precipitation and ion-exchange method. A variety of different techniques, including XPS, SEM, ICP-AES, TEM, XRD, BET, and Raman, are used to investigate the physicochemical performance of as-prepared materials. Their corresponding electrochemical performance is also evaluated through a 3- electrode system. Additionally, hybrid supercapacitors consisting of as-prepared carbon and transition metal electrodes are assembled, respectively, and their electrochemical performance is evaluated through the 2- electrode system

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24

Hall, Donald Lewis. "Fluid evolution during metamorphism and uplift of the massive sulfide deposits at Ducktown, Tennessee, U.S.A". Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54186.

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The Ducktown mining district, located in the southeastern corner of Tennessee within the Blue Ridge Province of the southern Appalachians, contains some of the largest metamorphosed pyrrhotite-pyrite-rich massive sultide deposits in the Appalachian-Caledonian orogen. Oxygen isotope temperatures of 530±20°C are consistent with previous estimates based on mineral thermobarometers (540±40°C; 6-7 kb) suggesting that minerals attained oxygen isotopic equilibrium during peak metamorphism and underwent little retrograde exchange. Fluid inclusion and petrologic data do not support the previous interpretation that low δ¹⁸O zones near orebodies are synmetamorphic, rather, a premetamorphic origin is indicated. Integrated fluid/rock ratios were low enough during and after metamorphism that premetamorphic spatial variations in δ¹⁸O were retained. However, hydrogen and carbon isotopes were homogenized throughout the area during or before metamorphism. The low δ¹⁸O zones surrounding the orebodies appear to have formed during sea—fIoor hydrothermal activity associated with ore deposition. The δ¹⁸O value of the fluid responsible for ore deposition, assuming a temperature of 300°C, is calculated to be -1 to +2 per mil, consistent with the interpretation that the ore fluid was modified seawater. Calculation of theoretical C-O-H-S fluid speciation suggests that the fluid in equilibrium with clinopyroxene-bearing rocks was essentially H₂O+CO₂with XCO₂ = 0.10. However, primary fluid inclusions located in clinopyroxene contain signifticant quantities of CH₄. This discrepancy is explained by hydrogen diffusion into primary fluid inclusions and subsequent conversion of CO₂ to CH₄ during uplift in response to an fH₂ gradient between inclusion and matrix fluids. Low δD values of primary fluid inclusions are consistent with diffusive addition of isotopically light hydrogen after trapping. Secondary inclusions in metamorphic quartz record a complex uplift history involving a variety of fluids in the C-O-H-N-salt system. lsochores calculated for these inclusions constrain the uplift path to have been initially concave toward the temperature axis. Over the pressure range 2.3 to 1.0 kb the uplift path became nearly isothermal at 215±20°C. lmmiscible H₂O-CH₄-N₂-NaCl fluids present during the isothermal stage of the uplift history were derived during Alleghanian thrusting by expulsion of pore fluids and maturation of organic matter in lower plate sedimentary rocks proposed to underlie the deposits. Average uplift rates of 0.1 mm/yr are suggested by the uplift path and available geochronologic data.
Ph. D.

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SWANSON, DALE DORSETT. "ELECTROCHEMICAL AND SPECTROSCOPIC STUDIES OF THIOETHER COORDINATION COMPLEXES (CYCLIC VOLTAMMETRY, OCTAHEDRAL LOW-SPIN METALS, BLUE COPPER PROTEINS, ELECTRON PARAMAGNETIC RESONANCE)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188102.

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The bis 1,4,7-trithiacyclononane (1,4,7-TTCN) complexes of iron, cobalt, nickel and copper are reported in this work. Their properties have been examined using computer-controlled electrochemical and spectroscopic techniques. These TTCN complexes form readily, are unusually symmetrical and support electron transfer reactions at the metal center. The cobalt(II) complex is octahedral, low spin and symmetrical. Four oxidation states of cobalt-TTCN complex are observed; two one-electron transfer processes are reversible. Copper (II) bis 1,4,7-TTCN is unusually symmetrical evidenced by both solid phase and ambient temperature aqueous phase electron paramagnetic resonance spectra. An unusually high redox potential for the copper complex indicates extraordinary stability of the Cu(I) oxidation state but evidently not at the expense of Cu(II) stability. The complex also has a high formation constant compared to other copper-thioether complexes. This unusual strength of thioether donor is attributed to ligand geometry. The 1,4,7-TTCN molecule is the only known cyclic polythioether to have all sulfur atoms endodentate. This structure contributes to thermodynamic stability of complexes as the ground state configuration of the free ligand is maintained in the complex.

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Gibbard, Kevin. "High temperature synthesis of cerium sulfides and kinetic modeling". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010471.

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Qu, Deyu. "The mechanism of adsorption of sulfides on gold(111)". Thesis, University of Ottawa (Canada), 1998. http://hdl.handle.net/10393/4384.

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In this thesis, we present the electrochemical and spectroscopic characterization of the monolayer on a Au(111) single crystal formed by alkanethiols, dialkyldisulfides and dialkylsulfides. We found that all these organic sulfur compounds adsorb dissociatively and form a monolayer of thiolates. We also study the monolayer formed by a cyclic sulfide, pentamethylene sulfide. We found that this sulfide forms a monolayer of an aldehyde terminated thiolate. We suggest that the sulfide is oxidatively dissociated by molecular oxygen and adsorb on the gold surface. A mechanism of this process is also described. We use S$\sb{\rm N}$2 chemistry to examine the reactivity of this cyclic sulfide. The fact that an S$\sb{\rm N}$2 reaction occurs on the gold surface proves the formation of a reactive chemisorbed sulfide on the gold surface.

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Qu, Deyu. "The mechanism of adsorption of sulfides on Au(111)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36735.pdf.

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Mizera, Michel-Adam. "Ignition temperature measurements of metallic sulfides in SHS processes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ37274.pdf.

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Condon, Brian D. "Stereoselective bond formation via lithiation of asymmetric acyclic sulfides". Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/29911.

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Mizera, Michel Adam. "Ignition temperature measurements of metallic sulfides in SHS processes". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28007.

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The quasi-steady-state ignition temperature was measured for the following metal-sulfur compounds: Cr-S, Mo-S, Mg-S, Mn-S, Si-S, Ti-S and Zn-S. The ignition temperatures for these mixtures ranged from 350$ sp circ$C to 600$ sp circ$C. For a same element (Mn) an increase in particle size of the metal reactant caused an increase in the ignition temperature of the mixture. For the Mn + S system, preliminary estimates using classical thermal explosion theory indicate that an apparently low activation energy reaction is present. Estimates of the activation energy derived from the results of transient ignition experiments involving Mn-S and Cr-S mixtures with large metal particle reactants yield similar low values. It is suggested that the classical method of solution using a high-activation energy assumption to solve the heat conduction equation modeling the reaction may be inappropriate. Modifications to the zeroth-order reaction term in the model which incorporate reactant consumption, diffusion kinetics or two-step reactions could improve modeling results.

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Sundberg, Jill. "Triboactive Low-Friction Coatings Based on Sulfides and Carbides". Doctoral thesis, Uppsala universitet, Oorganisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-230989.

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For sustainable development, it is highly important to limit the loss of energy and materials in machines used for transportation, manufacturing, and other purposes. Large improvements can be achieved by reducing friction and wear in machine elements, for example by the application of coatings. This work is focused on triboactive coatings, for which the outermost layer changes in tribological contacts to form so-called tribofilms. The coatings are deposited by magnetron sputtering (a physical vapor deposition method) and thoroughly chemically and structurally characterized, often theoretically modelled, and tribologically evaluated, to study the connection between the composition, structure and tribological performance of the coatings. Tungsten disulfide, WS2, is a layered material with the possibility of ultra-low friction. This work presents a number of nanocomposite or amorphous coatings based on WS2, which combine the low friction with improved mechanical properties. Addition of N can give amorphous coatings consisting of a network of W, S and N with N2 molecules in nanometer-sized pockets, or lead to the formation of a metastable cubic tungsten nitride. Co-deposition with C can also give amorphous coatings, or nanocomposites with WSx grains in an amorphous C-based matrix. Further increase in coating hardness is achieved by adding both C and Ti, forming titanium carbide. All the WS2-based materials can provide very low friction (down to µ<0.02) by the formation of WS2 tribofilms, but the performance is dependent on the atmosphere as O2 and H2O can be detrimental to the tribofilm functionality. Another possibility is to form low-friction tribofilms by tribochemical reactions between the two surfaces in contact. Addition of S to TiC/a-C nanocomposite coatings leads to the formation of a metastable S-doped carbide phase, TiCxSy, from which S can be released. This enables the formation of low-friction WS2 tribofilms when a Ti-C-S coating is run against a W counter-surface. Reduced friction, at a moderate level, also occurs for steel counter-surfaces, likely due to formation of beneficial iron sulfide tribofilms. The studied coatings, whether based on WS2 or TiC, are thus triboactive, with the ability to form low-friction tribofilms in a sliding contact.

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Porcelloni, Marina. "Synthesis and application of chiral sulfides in asymmetric epoxidation". Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272057.

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Nowosielska, Anna. "The leaching of metal sulfides in ammoniacal carbonate solutions". Thesis, Nowosielska, Anna (2017) The leaching of metal sulfides in ammoniacal carbonate solutions. Honours thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/40607/.

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The leaching of metal sulfides in ammoniacal solutions is of industrial importance for the production of copper, nickel and cobalt. In some processes, such as the Sherritt Gordon process, they are introduced as feed; while in others, such as the Caron process, they form in-situ, as intermediate products. The focus of this study is to understand the leaching behaviour of the in situ formed copper, nickel and cobalt sulfides, but the findings are expected to be relevant to the other related systems. The Caron process involves an oxidative dissolution of pre-reduced iron-based nickel and cobalt alloy grains in an aqueous solution containing ammonia and ammonium carbonate. Under the process conditions, these iron-based alloy grains undergo passivation because of the formation of an iron oxide surface layer, as nickel and cobalt become trapped within the passive iron matrix, resulting in reduced extractions. Thiosulfate ions have been reported to facilitate the leaching process. The presence of metal ammines and thiosulfate ions in the same system, however, has been observed to result in a formation of a metal sulfide layer on the surface of the dissolving iron-based alloy grains. This, on the other hand, results in a partial loss of nickel and cobalt from the solution, while also further increasing the tendency for iron passivation. It has been postulated, that after iron passivates, nickel and cobalt from the sulfide layer redissolve, however, there is little evidence of this, or the effect of process parameters on the rate and extent of such re-dissolution. The present study is aiming to shed some light on these processes. The dissolution of copper, nickel and cobalt sulfides was examined using three forms of these compounds - metal sulfides formed electrochemically (EFMS) under simulated Caron process leach conditions, synthetic monometallic metal sulfides (SMMS) and real metal sulfides, naturally found in ore (RMS). In the first instance, electrochemically formed metal sulfides were studied by techniques which included open circuit potential and cyclic voltammetry measurements. The dissolution rate and extent of the nickel, cobalt and copper from the metal sulfide was monitored. The leaching of the synthetic monometallic metal sulfides was carried out under similar conditions to those of the Caron process. The effects of key process parameters such as concentration of ammonia, concentration of ammonium carbonate and temperature were investigated. The pH and Eh of the studied systems were monitored and solution samples were analysed for Ni, Co and Cu. It was observed that the highest extraction of nickel and copper from their respective metal sulfides was at 3M [NH3]T + 1M [CO2]T at 60 °C, whereas the maximum extraction of cobalt from cobalt sulfide was observed at 5M [NH3]T + 1M [CO2]T at 45 °C. The kinetic data shows that leaching of nickel follows the ash layer diffusion model, with the activation energy for the process reported as ‘different’ at the different tested temperatures (69.6 kJ/mol at 25 °C and 14.7 kJ/mol at 60 °C). An attempt was made to derive the reaction orders with respect to ammonia (0.18) and ammonium carbonate (0.09). The available data is possibly not very reliable, however. The rate of copper leaching shows that the surface reaction model applies best to this system. The activation energy was 11.5 kJ/mol at 25 °C and 57.6 kJ/mol at 60 °C. The reaction order with respect to ammonia was 1.9 and for ammonium carbonate it was 4.0. The leaching kinetic data for cobalt from monometallic cobalt sulfide, showed that the process follows the surface reaction model similar to copper, with a steady activation energy of 6.5 kJ/mol. In contrast to nickel, the leaching of cobalt from cobalt sulfide had a higher order with respect to ammonium carbonate of 1.8 than with respect to ammonia of 0.9. The observed leaching behaviour of the electrochemically formed metal sulfides (EFMS) and the synthetic monometallic metal sulfides (SMMS) was compared to leaching of real metal sulfides naturally found in ore (RMS) by testing flotation concentrate under the conditions which gave the highest extractions for the former. Tested were two types of flotation concentrate, one containing high nickel sulfide and another containing high copper sulfide. A sample of cobalt sulfide was not available. In these experiments, the effect of adding 0.25M sodium sulfite (Na2SO3) was also examined. The results have shown that the addition of sulfite improved both rate and extent of the extraction of nickel. It significantly hindered the extraction of copper, however. Namely, the rate of nickel extraction with sodium sulfite present was approximately 1.31 mg/L/min vs. 0.07 mg/L/min without it. The rate of copper extraction on the other hand, decreased from 4.09 mg/L/min without sodium sulfite, to just 0.89 mg/L/min when it was added. On the basis of this data, and assuming similar behaviour between copper and cobalt sulfides, it does not appear that addition of sodium sulfite could reduce the losses of copper and cobalt from the system.

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Walton, Richard I. "The characterisation and structure of amorphous and poorly crystalline transition-metal chalcogenides". Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388467.

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Schumer, Benjamin Nathan, i Benjamin Nathan Schumer. "Mineralogy of Copper Sulfides in Porphyry Copper and Related Deposits". Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/626163.

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Porphyry copper deposits represent one of the largest copper reserves on Earth. They typically contain large, low-grade reserves of primary ore and higher-grade, supergene enrichment blankets of sulfide and oxide ores. Understanding the mineralogy of porphyry copper ores and ores related to porphyry copper systems is exceedingly important for several reasons, foremost of which are the information provided by ore mineral parageneses, assemblages, and mineral chemistry on evolution of these magmatic-hydrothermal systems, and information on mineral processing characteristics of the ores. The focus of this work is to better understand the mineralogy of supergene copper sulfides in porphyry copper systems and hypogene base metal lodes related to porphyry copper systems, and use this mineralogical knowledge to improve our understanding of the processes responsible for ore formation. The objectives of this study are accomplished by two means: focusing on the crystallography and crystal chemistry of minerals, and then applying this mineralogical knowledge to a supergene sulfide enrichment blanket and hypogene massive sulfides from base metal lodes in southeastern Arizona. The discovery of a new mineral, natropalermoite, NaSr2Al4(PO4)4(OH)4, provided the opportunity to use single-crystal X-ray diffraction to solve a crystal structure, and electron-probe microanalysis (EPMA) to study the crystal chemistry of natropalermoite and how the accommodation of Na in the structure changes lengthens the unit cell along [010] and shortens it along [100] and [001] compared to its lithium analogue, palermoite. Solution of the crystal structure of the mineral nickelskutterudite, (Ni,Co,Fe)As3, allowed for the investigation of anion deficiency in minerals of the skutterudite group, a problem whose solution has eluded researchers for nearly 100 years. Two skutterudite (CoAs3) and two nickelskutterudite samples were analyzed using single-crystal X-ray diffraction, EPMA, and procrystal electron density. The results showed fully-occupied anion sites and a cation surplus, which was accommodated in the icosahedral site, proving that minerals of the skutterudite group are not anion deficient. This mineralogical knowledge was applied to the supergene enrichment blanket in the Western Copper section of the Morenci mine, Greenlee County, and hypogene massive sulfide deposits associated with a porphyry copper deposit at Bisbee, Cochise County, Arizona. This is one of very few studies of supergene sulfide blankets ever completed. One drill hole through the supergene blanket at Western Copper was examined using ore microscopy and EPMA. Results showed dominant (Cu+Fe):S ratios of 1.80 ± 0.05, 1.92 ± 0.03, and 1.10 ± 0.10, with higher (Cu+Fe):S dominant high in the blanket and low ratios dominant near the base of the blanket. These values were interpreted to be controlled by activity of Cu2+, Fe2+, and Fe3+ in solution. Massive sulfide deposits at Bisbee were investigated using ore microscopy and EPMA in order to correct the previous conflicting reports of the mineralogy and paragenesis of this famous district and interpret constraints on conditions of ore-forming fluids. Results show four types of ore: chalcopyrite-rich with hematite and/or pyrite, bornite-rich, chalcocite-rich, and a Zn-Pb association. Chalcopyrite-rich ores formed first, followed by bornite-rich and chalcocite-rich ores. All ores were formed at relatively shallow depths from oxidized, moderately sulfur-rich fluids; early fluids were higher temperature and later fluids were lower temperature and considerably more sulfidized. Zinc-lead ores formed early and were continuously dissolved and reprecipitated distal to Cu-mineralization. These patterns are similar to many other base-metal lode districts worldwide, however Bisbee contains more Zn-Pb ore than other districts with hematite-containing ores and less than those without hematite.

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Ku, James Chih-Hung. "Studies on the electrochemistry of some mineral and organic sulfides". Thesis, University of Ottawa (Canada), 1985. http://hdl.handle.net/10393/4806.

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Xie, Ning. "Lewis acid catalyzed oxidation of sulfides and sulfoxides by permanganate". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq35823.pdf.

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Phillips, Noel William. "The environmental controls of iron(II) sulfides in natural waters". Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310360.

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Eversfield, Sharon Gail. "An investigation of some disordered transition metal sulfides and cyanides". Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288770.

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Peters, Emily Sarah. "Precursor synthesis and chemical vapour deposition of transition metal sulfides". Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408505.

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Herbert, Francis William. "Mechanisms governing the growth, reactivity and stability of iron sulfides". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98126.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 135-140).
The kinetics of electrochemical processes in ionic materials are fundamentally governed by dynamic events at the atomic scale, including point defect formation and migration, and molecular interactions at the surface. A corrosion system comprising an iron sulfide film (passive layer) formed on iron or steel in contact with an hydrogen sulfide (H₂S)- rich fluid can thus, in principle, be modeled by a series of unit reaction steps that control the rate of degradation under given thermodynamic conditions. This overarching thesis goal necessitates a concerted experimental and computational approach to determine the relevant kinetic parameters such as activation barriers Ea and rate constants v₀ for the homogeneous and heterogeneous reactions of interest. These fundamental values can be obtained experimentally via temperature-dependent measurements on pure, model iron sulfide samples. This thesis therefore consists of three case studies on the stable Fe-S phases pyrrhotite (Fe₁-xS) and pyrite (FeS₂) to identify the elementary corrosion mechanisms and their kinetic parameters. Pyrrhotite is of interest because the off-stoichiometry of this phase leads to relatively rapid bulk processes such as diffusion; pyrite has a comparitively inert bulk but this work showed that it has a chemically labile surface. The first study focuses on two basic, rate-controlling steps in the growth of pyrrhotite: cation diffusion and sulfur exchange at the surface. First, iron self-diffusivity *DFe is determined across the temperature range 170-400 °C through magnetokinetic studies of the diffusion-driven "[lambda]" magnetic transformation, as well as direct tracer diffusion measurements in Fe₁-xS crystals using secondary ion mass spectrometry (SIMS). This range encompasses the sponteneous magnetic and structural order-disorder temperature TN = 315 °C in pyrrhotite. The effect of spontaneous magnetization below TN is to increase the Fe vacancy migration energy by a combined 40% increasing Ea for diffusion from 0.83 eV in paramagnetic Fe₁-xS to ~1.20 eV in the fully magnetized state. An extrapolation of the Arrhenius law from the paramagnetic regime would therefore overestimate actual diffusivities by up to 10² times at 150 °C. Second, the surface exchange of sulfur from H₂S into the solid state in Fe₁-xS is measured using electrical conductivity relaxation, yielding Ea = 1.1 eV for sulfur incorporation into pyrrhotite. With their similar thermal dependence, there is no clear temperature crossover from cation diffusion- to surface exchange-limiting regimes, or vice versa. Instead, surface exchange is expected to constrain pyrrhotite growth for films under ~100 [mu]m thickness, beyond which diffusion becomes the rate limiting mechanism, independent of external driving factors such as temperature. The second study explores the role of surface electronic states on the electrochemical reactivity of pyrite. Charge transfer between a solid surface and an adsorbate such as H₂S requires the mutual availability of filled/empty electronic states at the same energy level. The semiconducting FeS₂(100) surface is predicted to have intrinsic surface states (SS's) from Fe and S dangling bonds, as well as extrinsic SS's related to delocalized defects at the surface, both of which would affect charge transfer characteristics. A novel, broadly-applicable methodology is developed in this thesis to quantify the energy and density of these SS's, based on experimental scanning tunneling microscopy / spectroscopy (STM/STS) in conjunction with first principles tunneling current modeling. As a result, a decreased surface band gap Eg of 0.4 eV, compared to 0.95 eV in bulk pyrite, is measured. The findings highlight the need to differentiate between bulk and surface electronic structure when assessing heterogeneous reactivity, and have implications for the use of FeS₂ in potential technological applications, for example as a photovoltaic adsorber. Finally, the dynamics of point defect formation and clustering on FeS₂(100) under high-temperature, reducing conditions are investigated to understand the stability of the surface under extreme conditions. Synchrotron x-ray photoelectron spectroscopy (XPS) is used to measure a formation energy [delta]Hf for sulfur vacancies in the topmost atomic layer of 0.1 eV up to approximately 240 °C. Above this temperature, however, point defects are shown to condense into surface pits as measured by scnaning tunneling microscopy (STM). The combined, experimental XPS and STM results are replicated with high precision by a kinetic Monte Carlo (kMC) simulation, developed by Aravind Krishnamoorthy towards his doctoral thesis, of surface degradation on realistic length-and timescales of 10-¹⁰ - 10-⁷ m and up to several hours, respectively. The findings have implications for the initiation of surface breakdown via pitting in ionic passive films, as well as providing a broader understanding of the non-stoichiometry of the pyrite surface. The common thread is a focus on events at the atomic and electronic scale, with an emphasis on point defects. The results thereby facilitate a bottom-up approach to modeling electrochemical processes such as corrosion in Fe-S phases, in which the unit steps are cast into probabilistic simulation tools. While the three studies here comprise only a partial examination of the atomic-scale events regulating the behavior of Fe-S passive layers, this approach makes inroads towards more accurate component lifetime prediction and the design of robust materials for aggressive environments. Moreover, the fundamental surface and bulk physical chemistry of iron sulfides explored in this work has implications beyond corrosion to other uses of these materials, including potential magnetic devices (Fe₁-xS) and earth-abundant photovoltaic and photoelectrochemical adsorbers (FeS₂).
by Francis William Herbert.
Ph. D.

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Brown, Bruce N. "The Influence of Sulfides on Localized Corrosion of Mild Steel". Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1386325647.

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44

Yavuz, Sinem. "Seismic characterization of Volcanogenic massive sulfides – the Semblana orebody, Portugal". Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/48.

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The exploration at Neves Corvo was further progressed through specialised elastic property measurements and PRA processing. Unambiguous imaging of the known VMS deposit was achieved through pre-stack imaging, followed by the calibration of seismic data with sonic and pseudo logs, which was an integral part of the volumetric interpretation. Quantitative interpretation of the Semblana deposit’s was performed with acoustic and elastic impedance inversion and AVO analysis, which demonstrated the unique nature of massive sulfide response.

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45

Young, Aidan Gerard, i n/a. "Chemistry at cadmium sulfide surfaces". University of Otago. Department of Chemistry, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080806.164202.

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Probing the surface chemistry of thiol ligand binding to cadmium chalcogenide nanoparticles is important to clarify factors involved in quantum dot stability and surface functionalisation. This research is a spectroscopic investigation aimed at gaining a better understanding of the interaction/bonding of various ligands to CdS, with respect to the use of CdS in biological imaging. The findings of this research are important to the more general field of cadmium chalcogenide materials as biological imaging agents. Deposited CdS nanoparticle films were used in this work as model quantum dot surfaces for ligand adsorption studies. The adsorption of the monothiol-containing ligands, mercaptoacetic acid, mercaptopropionic acid, and mercaptoethanol, to CdS thin films were studied in situ using attenuated total reflectance infrared spectroscopy. The absence of an S-H stretch absorption for the adsorbed species showed that adsorption occurred via the deprotonated thiol group. The adsorption of the dithiol-containing ligands α-lipoic acid, dihydrolipoic acid, and dithiothreitol to CdS nanoparticle films was investigated. The adsorption of dihydrolipoic acid and dithiothreitol was found to occur via both thiol functional groups and an additional interaction between the carboxylate group and the CdS surface. The adsorption of α-lipoic acid to CdS in the presence of light proceeded with photo-oxidation of the CdS surface and reductive cleavage of the disulfide bond of α-lipoic acid to produce some adsorbed dihydrolipoic acid and thiosulfate. The adsorption of α-lipoic acid to CdS in the absence of visible light showed no photo-oxidation, and suggested adsorption occurred via retention of the disulfide bond. The kinetics of adsorption and desorption of oxalic acid on deposited anatase TiO₂ films were studied to investigate the feasibility of extracting molecular information from attenuated total reflectance infrared spectroscopic kinetic data of ligand processes on deposited particle films. Oxalic acid adsorbed on anatase TiO₂ is a well-studied example and is reported to result in three different surface species. The profile of the desorption data indicated contributions from three different components. Different component contributions were unable to be obtained from the adsorption data which is attributed to adsorption occurring much faster than desorption and thus being relatively insensitive to the presence of different adsorbed species. The kinetics of adsorption and desorption of mercaptoacetic acid on CdS were investigated. The desorption data profile indicated the presence of two adsorbed species with different affinities for the CdS surface, the exact chemical nature of which can only be speculated upon given the absence of distinguishing IR spectral features. Ligand exchange reactions at the surface of oleate and trioctylphosphine oxide-capped CdS quantum dot films were investigated. Adsorbed oleate was coordinated to the CdS in a chelating bidentate manner through the carboxylate functional group, while adsorbed trioctylphosphine oxide was coordinated though the P=O functional group. Ligand exchange reactions on the oleate and trioctylphosphine-capped CdS films were studied, and exchange with monothiol-containing ligands was observed only at solution pH where the exchanging ligand was uncharged. Avidin-biotin bioconjugation reactions were carried out on CdS films, which involved the sequential adsorption of mercaptoacetic acid, the protein avidin, and the subsequent binding of the ligand biotin. The spectral data suggested that avidin underwent a conformational change upon adsorption to the CdS surface. This conformation appeared to be perturbed again upon binding of biotin, and it is speculated that the conformation partially reverted back to the native solution conformation.

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46

MARTINS, ELAINE A. J. "Sintese e caracterizacao de sulfetos metalicos em baixas temperaturas por reacao solido-solido utilizando-se gerador de sulfeto". reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11009.

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Made available in DSpace on 2014-10-09T12:46:52Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T13:58:05Z (GMT). No. of bitstreams: 1 08512.pdf: 4971310 bytes, checksum: 6e08f69ed4ae0331760f78b901cc4142 (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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47

Mayende, Lungisa. "Isolation of a Clostridium Beijerinckii sLM01 cellulosome and the effect of sulphide on anaerobic digestion". Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1004032.

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Cellulose is the most abundant and the most resistant and stable natural organic compound on earth. Enzyme hydrolysis is difficult because of its insolubility and heterogeneity. Some (anaerobic) microorganisms have overcome this by having a multienzyme system called the cellulosome. The aims of the study were to isolate a mesophilic Clostridium sp. from a biosulphidogenic bioreactor, to purify the cellulosome from this culture, to determine the cellulase and endoglucanase activities using Avicel and carboxymethylcellulose (CMC) as substrates and the dinitrosalicyclic (DNS) method. The organism was identified using 16S rDNA sequence analysis. The sequence obtained indicated that a strain of Clostridium beijerinckii was isolated. The cellulosome was purified from the putative C. beijerinckii sLM01 host culture using affinity chromatography purification and affinity digestion purification procedures. The cellulosomal and non-cellulosomal fractions of C. beijerinckii sLM01 were separated successfully, but the majority of the endoglucanase activity was lost during the Sepharose 4B chromatography step. These cellulosomal and non-cellulosomal fractions were characterised with regards to their pH and temperature optima and effector sensitivity. Increased additions of sulphide activated the cellulase activity of the cellulosomal and non-cellulosomal fractions up to 700 %, while increased additions of sulphate either increased the activity slightly or inhibited it dramatically, depending on the cellulosomal and non-cellulosomal fractions. Increased additions of cellobiose, glucose and acetate inhibited the cellulase and endoglucanase activities. pH optima of 5.0 and 7.5 were observed for cellulases and 5.0 for endoglucanases of the cellulosomal fraction. The noncellulosomal fraction exhibited a pH optimum of 7.5 for both cellulase and endoglucanase activities. Both fractions and enzymes exhibited a temperature optimum of 30 °C. The fundamental knowledge gained from the characterisation was applied to anaerobic digestion, where the effect of sulphide on the rate-limiting step was determined. Sulphide activated cellulase and endoglucanase activities and increased the % chemical oxygen demand (COD) removal rate. Levels of volatile fatty acids (VFAs) were higher in the bioreactor containing sulphide, substrate and C. beijerinckii. Sulphide therefore accelerated the rate-limiting step of anaerobic digestion.

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48

Woolfall, Marc P. "Novel mediators for oxidation using hydrogen peroxide". Thesis, University of Liverpool, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367254.

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Feaviour, Mark R. "Synthesis, characterisation and reactions of molybdenum and tungsten chalcogenides". Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314313.

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Raza, Muhammad Rehail. "Synthesis and chemistry of novel chiral sulfilimines". Thesis, Keele University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311151.

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