La préparation de nouveaux catalyseurs à base de tungstène par la voie Chimie Organométallique de Surface a été abordée dans cette thèse pour la production du propylène à partir de l'éthylène et/ou de butènes. Deux types de systèmes catalytiques ont été développés. Des hydrures de tungstène supportés, obtenus par réaction de surface entre un complexe de tungstène [W(CtBu)(CH2 tBu)3] et la -alumine suivi d'un traitement sous H2 à 150°C ont été préparés. Les caractérisations par différentes techniques spectroscopiques (IR, RMN solide, Raman et EXAFS) et réactivité stoechiométrique ainsi que les modélisations par calculs théoriques (DFT) ont montré la présence à la surface de deux espèces trishydrures : neutre et cationique. Ce catalyseur s'est révélé particulièrement actif pour la conversion directe de l'éthylène en propylène à 150°C selon un mécanisme trifonctionnel (dimérisation, isomérisation et métathèse croisée). L'accent a été mis sur la détermination du mode de désactivation par oligomérisation de l'éthylène, due principalement à la présence en surface d'espèce cationique. Pour pallier ce problème, d'autres réactions permettant la production de propylène avec de meilleures activités ont été développées (conversion des butènes, métathèse croisée éthylène/2-butène, 2-butène/isobutène). La conversion directe de 2-butène en propylène, inconnue jusqu'à lors, a notamment été étudiée. Enfin, un second type de systèmes catalytiques, modèles du site actif de l'hydrure de tungstène supporté et du catalyseur industriel WO3/SiO2, a été préparé et caractérisé. Ces nouveaux catalyseurs, portant un ligand oxo, se sont montrés bien plus actif en métathèse des oléfines que leurs homologues portant un ligand imido. Ces derniers se désactivent rapidement par décomposition de métallacyclobutane entraînant une réduction du tungstène non observée dans le cas des systèmes oxo / The preparation of new tungsten based catalyst using Surface Organometallic Chemistry is described in this thesis. These catalysts have been prepared for the production of propylene from ethylene and/or butenes. Two types of catalyst have been developed. Supported tungsten hydrides, resulting from the surface reaction of [W(CtBu)(CH2 tBu)3] with -alumina followed by a treatment under H2 at 150°C have been prepared. The characterizations by several spectroscopic techniques (IR, SSNMR, Raman and EXAFS) and stoichiometric reactivity combined by with theoretical calculations (DFT) have demonstrated the presence of two tungsten hydride surface species: a neutral and a cationic. This catalyst have shown outstanding reactivity for the direct conversion of ethylene to propylene 150°C following a tri-functional mechanism (dimerization, isomerization and crossmetathesis). The deactivation pathway has been attributes to ethylene oligomerization mainly due to the presence of cationic surface species. To circumvent this deactivation, other reactions affording propylene have been developed (butenes conversion, ethylene/2-butene and isobutene/2-butene cross metathesis). The conversion of 2-butene to propylene, until then unreported, has been notably studied. Finally, a second type of catalyst, models of the active site of supported tungsten hydrides and of WO3/SiO2 catalyst, has been prepared and characterized. These new catalysts, bearing an oxide ligand, have been shown to be more active than their imido counterparts. These later deactivates quikely by metallacyclobutane decomposition leading to the reduction of the tungsten non observed in the case of oxo systems

[pt] Sistemas Mo/Al2O3 e W/ZrO2 foram estudados a fim de evidenciar se a reação WO3+ZrO2 ocorre no estado sólido, e se a reação MoO3+Al2O3, também no estado sólido, ocorre com aluminas porosas. Para tanto, essas misturas foram preparadas utilizando-se dois teores de Mo e de W, respectivamente: 5 e 10 µmolMo/m2 de suporte alumina e 10 e 16 µmolW/m2 de suporte zircônia sendo tratadas a 773 K. Para o caso dos sistemas Mo/Al2O3, foram utilizadas três aluminas com diferentes propriedades, tais como: área específica, porosidade, grau de hidroxilação e distribuição de grupos OH superficiais. Para os sistemas W/ZrO2, verificou-se também o efeito de temperatura de tratamento mais elevada: 973 K. Todas as amostras obtidas foram caracterizadas pelas técnicas de: difração de raios-X, adsorção de N2, espectroscopia de absorção na região do infravermelho e de reflectância difusa no UV-visível. Considerando-se os sistemas Mo/Al2O3, verificou-se que o MoO3 reagiu com as três aluminas, apesar da maior dificuldade de difusão de massa devido à textura das aluminas porosas, formando estruturas de Mo diferentes do óxido original, sendo que a maior dispersão, sobre o suporte, das espécies de Mo geradas parece estar relacionada à presença de grupos hidroxila mais básicos. Para os sistemas W/ZrO2, os resultados também evidenciaram que foram geradas espécies de tungstênio diferentes do WO3 original, sendo que a utilização da maior temperatura de calcinação levou à formação de mais espécies de W dispersas sobre o suporte. / [en] Mo/Al2O3 and W/ZrO2 systems have been studied in order to verify if the WO3+ZrO2 reaction occurs in solid state, and if the MoO3+Al2O3 reaction also occurs with porous alumina in the solid state. These mixtures were prepared using two Mo and W loadings: 5 and 10 µmolMo/m2 of support alumina and 10 and 16 µmolW/m2 of support zirconia, and they were calcined at 773 K. For Mo/Al2O3 systems three aluminas with different properties, such: specific area, porosity, hydroxylation degree, and OH groups distribution were used. For W/ZrO2 systems the effect of a higher treatment temperature: 973 K was also evaluated. All samples were characterized by the following techniques: X- ray diffraction, N2 adsorption, infrared absorption spectroscopy, and UV-vis diffuse reflectance spectroscopy. For Mo/Al2O3 systems it has been verified that molibdenum oxide reacted with the aluminas even though the mass transfer difficulties related to the porosity, forming Mo structures distinct from MoO3, which higher Mo dispersion may be related to more basic hydroxyl groups. For W/ZrO2 systems, the results have also shown that W species different from WO3 were obtained, and higher calcination temperature promoted the formation of more dispersed species onto the support.

The main object of this work is the technology of radio frequency controlled inductively coupled plasma, abbreviated RF-ICP. The specific goal of the work was the application of surface layers of tungsten and analysis of the influence of changes in process conditions on the resulting microstructure and chemical composition of deposited coatings. The monitored conditions were torch power, choice of carrier gas, powder feedrate.

This work can be divided into two parts. In the first part, we examine possibilities of preparation of monocrystalline tungsten and tungsten oxide nanoclusters by means of magnetron sputtering with gas aggregation. Clusters are prepared in the non-reactive (Ar) and reactive (Ar + O2) atmosphere and heated after the deposition or during the flight by IR radiation. Influence of oxygen in the aggre- gation process was described and possibilities of generating crystalline tungsten and tungsten oxide clusters were found. In the second part, we study reactivity of tungsten oxide layers, pure and doped with rare metals (Pt, Au), deposited on the silicon wafer and etched carbon, towards partial methanol oxidation. Influence of carbon substrate and metal doppants on reactivity was found and described, along with mofrological and chemical changes that occurs in the sample during the proces. 1

Die SME AG ist das erste Bergbauunternehmen, das seit Jahrzehnten ein neues Erzbergwerk erschließen und in Betrieb nehmen will. Traditionsreiche Bergbauunternehmen haben in der Vergangenheit neue Standorte, auf der Grundlage vorhandener Personalstrukturen, vorhandener Technik und Technologien, erschlossen. Im nachfolgenden Beitrag wird die strategische Herangehensweise der SME AG beschrieben, um zeitnah mit der Gewinnung in der Wolfram-Zinn-Lagerstätte zu beginnen.

Thermal reactions and flash photolysis are used to study the olefin bond-migration promoted by tungsten carbonyls. Substitution of piperidine (pip) by 2- allylphenyldiphenylphosphine (adpp) in the cis-(pip)(η^1- adpp)W(CO)-4 complex was investigated, and no olefin bond-migration was observed. This suggests that a vacant coordinated site adjacent to the coordinated olefin is an essential requirement for olefin bond rearrangement. The rates of olefin attack on the photogenerated coordinatively unsaturated species, cis-[(CB)(η^1-ol- P)W(CO)-4] (CB = chlorobenzene, p-ol = Ph-2P(CH-2)-3CH=CH-2; n = 1-4) were measured. Kinetics data obtained both in pure CB and in CB/cyclohexane mixtures support a dissociative mechanism in which the W-CB bond is broken in the transition state. In contrast to results observed in studies of other related systems, no olefin bond-migration is noted. This observation is attributed to P-W coordination at all stages of the reaction, which precludes formation of a reactive intermediate containing a vacant coordination site adjacent to a P-ol bond.

In this Master Thesis work, the effect of pressure on sintering of cemented carbides is investigated. Special focus hasbeen given to the residual porosity after sintering. It is well known that sintering shrinkage depends on binder phasecontent, grain size, temperature and pressure. Thus 4 different cemented carbides grades were selected. The gradeswere pressed into standard products and TRS (Tensile Rupture Strength) rods with two different shrinkage factors.These were then sintered at different pressures and temperatures. Thereafter the impact of pressure on propertiessuch as Density, Coercivity, Porosity and TRS were analyzed. The observations were further supported with Weibullprobability analysis and fracture surface analysis in SEM.It has been shown that there exists a distinct threshold pressure at which significant reduction in porosity occurs forgiven compacted densities. For 3 out of 4 cemented carbide grades it has been observed that P2 sintering pressure issufficient to meet desired product characteristics. The fourth grade required a minimum sintering pressure of P4 toachieve desired quality criteria. Moreover it has been concluded that an increased sintering pressure increasesmaterial strength, as compared to vacuum sintering, thereby reducing the amount of early failures caused by poresduring TRS test.                                    Keywords: Cemented Carbides, Pressurized Sintering, Tungsten carbide, Porosity, Vacuum sintering, TensileRupture Strength, Weibull analysis, Fracture surface analysis.

Indiana University-Purdue University Indianapolis (IUPUI) / The field of two-dimensional (2D) nanomaterials first began in earnest with the discovery of graphene in 2004 due to their unique shape-dependent optical, electronic, and mechanical properties. These properties arise due to their one-dimensional confinement and are further influenced by the elemental composition of the inorganic crystal lattice. There has been an intense focus on developing new compositions of 2D nanomaterials to take advantage of their intrinsic beneficial properties in a variety of applications including catalysis, energy storage and harvesting, sensing, and polymer nanocomposites. However, compared to the field of bulk materials, the influence of surface chemistry on 2D nanomaterials is still underdeveloped. 2D nanomaterials are considered an “all-surface” atomic structure with heights of a single to few layers of atoms. The synthetic methods used to produce 2D materials include bottom-up colloidal methods and top-down exfoliation related techniques. Both cases result in poorly controlled surface chemistry with many undercoordinated surface atoms and/or undesirable molecules bound to the surface. Considering the importance surfaces play in most applications (i.e., catalysis and polymer processing) it is imperative to better understand how to manipulate the surface of 2D nanomaterials to unlock their full technological potential. Through a focus of the ligand-surface atom bonding in addition to the overall ligand structure we highlight the ability to direct morphological outcomes in lead free halide perovskites, maximize optoelectronic responses in substoichiometric tungsten oxide, and alter physicochemical properties titanium carbide MXenes. The careful control of precursor materials including poly(ethylene glycol) (PEG) surface ligands during the synthesis of bismuth halide perovskites resulted in the formation of 2D quasi-Ruddlesden-Popper phase nanomaterials. Through small angle X-ray scattering (SAXS) and in conjunction with X-ray photoelectron spectroscopy (XPS) we were able to conclude that an in-situ formation of an amino functional group on our PEG-amine ligand was inserted into the perovskite crystal lattice enabling 2D morphology formation. Additionally, through UV-vis absorption and ultraviolet photoelectron spectroscopies we were able to develop a complete electronic band structure of materials containing varying halides (i.e., Cl, Br, and I). Furthermore, through the increased solubility profile of the PEG ligands we observed solvent controlled assemblies of varying mesostructures. We developed an ex-situ ligand treatment to manipulate the localized surface plasmon resonance (LSPR) response of anion vacancy doped tungsten oxide (WO3-x) nanoplatelets (NPLs). Upon ligand treatment to alter the surface passivating ligand from carboxylic acid containing myristic acid (MA) to tetradecylphosphonic acid (TDPA) we observed a >100 nm blue shift in the LSPR response. Using Fourier transform infrared (FTIR) and Raman spectroscopies in conjunction with DFT calculated Raman spectra we were able to conclude this shift was due to the formation of tridentate phosphonate bonds on the NPLs surface. Phosphonate bonding allows for an increase in surface passivation per ligand decreasing surface trapped electrons. These previously trapped electrons were then able to participate as free electrons in the LSPR response. Electron paramagnetic spectroscopy (EPR) further supported this decrease in surface traps through a decrease and shift of the EPR signal related to metal oxide surface trapped electrons. Lastly, using our knowledge of PEG ligands we were able to modify esterification chemistry to covalently attach PEG ligands to a MXene surface. The successful formation of an ester bond between a carboxylic acid containing PEG ligand and hydroxyl terminating group on the MXene surface was supported by FTIR spectroscopy and thermogravimetric analysis. The attachment of PEG resulted in a drastic change in the hydrophilicity of the MXene surface. Where MXenes were previously only processed in extremely polar solvents the PEG attachment allowed for high dispersibility in a wide range of polar and non-polar organic solvents, effectively increasing their processability. Further, this chemistry was modified to include an additional functional group on the PEG ligand to increase the valency of the post-modification MXene nanoflakes. Overall, work presented in this dissertation represents the development and application of surface chemistry to relatively new 2D nanomaterials. We believe our work significantly increases the knowledge of 2D halide perovskite formation, manipulation of LSPR active metal oxide materials, and the future processing of MXene materials.

Inhalative Partikel können gesundheitsschädigende Wirkungen im Respirationstrakt ausüben. Für Hartmetallstäube aus Wolframcarbidcobaltpartikeln wurden in epidemiologischen Studien Zusammenhänge mit dem Auftreten einer chronisch fibrotischen Lungenerkrankung aufgezeigt, der Hard Metal Lung Disease (HMLD). Zur Aufklärung ihrer Pathogenese wurden die biologischen Effekte mikroskaliger Wolframcarbidpartikel erforscht. Seit einigen Jahren werden zunehmend Pulver zur Herstellung von Hartmetall verwendet, deren Partikel Durchmesser im Nanometerbereich aufweisen. In der vorliegenden Arbeit wurden daher in vitro die Effekte nanoskaliger Wolframcarbidpartikel an humanen Zellen untersucht. Dabei wurden Partikelsuspensionen mit unterschiedlichen Partikelgrößen und –zusammensetzungen verglichen. Beurteilt wurden die Aufnahme der Partikel in die Zellen, ihre toxikologische Wirkung und inflammatorische Mediatoren, die die exponierten Zellen als Reaktion auf die Partikel sezernierten. In Bezug zur Exposition durch Inhalation wurden eine Lungenepithelzelllinie, eine Monozytenzelllinie und primäre mononukleäre Zellen aus dem Blut untersucht. Es zeigte sich, dass die beobachteten Effekte sowohl partikelspezifisch als auch zelltypspezifisch variierten. Dabei wurden die Partikel in alle Zelltypen aufgenommen mit den stärksten Internalisierungsraten in humanen primären Monozyten. Die Wolframcarbidcobalt-Partikel wirkten im Allgemeinen am stärksten vitalitätsmindernd. Alle Partikelarten bewirkten in primären Monozyten eine stark erhöhte Produktion von Zytokinen und Chemokinen. Untersuchungen zum Mechanismus der Partikeleffekte wiesen auf die Beteiligung reaktiver Sauerstoffspezies hin. Es konnten in der vorliegenden Arbeit bestehende Erkenntnisse zur Toxizität von Wolframcarbidcobaltpartikeln bestätigt werden und Hinweise auf die Beeinflussung biologischer Effekte durch verschiedene Partikelgrößen und Oberflächeneigenschaften von Nanopartikeln gefunden werden.

Le but principal de ces travaux de thèse fut la conception et la réalisation de biocapteurs par utilisation de méthodes de transduction sans marquage, comme la spectroscopie d’impédance électrochimique (EIS), pour la détection de cible d’intérêts. Pour cela, différentes architectures moléculaires, spécifiques à la molécule d’intérêt ciblée, ont été développées afin de permettre la transduction du signal issu de la reconnaissance entre le biorécepteur et son substrat, et conduire ainsi à la détection de la cible.Les systèmes mis au point reposent sur l’intégration de nanomatériaux, tels que les nanotubes de carbones ou le disulfure de tungstène, pour assurer l'immobilisation de l'entité biospécifique à la surface du capteur. L’intérêt de ces matériaux est multiple puisqu’ils permettent une très forte augmentation de la surface spécifique du système et sont également mis à contribution lors de la fonctionnalisation de la surface de l’électrode. Un des grands défis rencontré dans le développement des biocapteurs étant la stratégie d'immobilisation de l'entité biospécifique sur la surface du capteur.Ces travaux se sont donc dans un premier temps intéressés à la réalisation et à la caractérisation de films minces de ces nanomatériaux ainsi qu’à leur transfert à la surface d’une électrode. Dans ce contexte, le but est de concevoir des bioarchitectures poreuses à base de polymères fonctionnels électrogénérés autour des nanostructures de carbone permettant la pénétration de grandes biomolécules comme des anticorps pour développer des immunocapteurs de haute performance.La seconde partie de ce travail s’est donc orientée vers la conception de biocapteurs par utilisation de ces différents matériaux. La fiabilité du procédé de la construction de ces nanostructures poreuses a été validée par la conception de systèmes immunologiques pour la détection de l’anticorps de l’antitoxine du choléra et l’anticorps de la toxine de la dengue.Enfin, un dernier biocapteur enzymatique, s’appuyant sur l’utilisation de nano-bâtonnets de disulfure de tungstène, a été développé. Ce dernier permet la détection de deux molécules d’intérêts, à savoir le catéchol et la dopamine, par utilisation de la polyphénol oxydase. / The main purpose of this work was the design and the development of biosensors by using non-marking transduction methods, such as electrochemical impedance spectroscopy (EIS), for the detection of targets of interests. To this end, various molecular architectures have been developed to allow the transduction of the signal resulting from the recognition between the bioreceptor and its substrate, and thus lead to the detection of the target.The systems developed are based on the integration of nanomaterials, such as carbon nanotubes or tungsten disulfide, to ensure the immobilization of the biospecific entity at the surface of the sensor. The advantages of these materials are multiples, since they allow a very large increase in the specific surface area and are also used in the functionalization of the surface of the electrode. Indeed, one of the major challenges encountered in the development of biosensors is the strategy involved in the immobilization of the biospecific entity on the surface of the sensor.This work was initially interested in the realization and characterization of thin films of these nanomaterials as well as their transfer to the surface of an electrode. In this context, the aim is to design porous bioarchitectures based on electrogenerated functional polymers around carbon nanostructures allowing the penetration of large biomolecules such as antibodies to develop high-performance immunosensors.The second part of the work was oriented towards the design of biosensors using these different materials. The reliability of the process has been validated by the design of immunological systems for the detection of the anti-cholera toxin antibody and dengue toxin antibody.Finally, a last enzymatic biosensor, based on the use of tungsten disulfide nano-sticks, has been developed. The latter allows the detection of two molecules of interest, catechol and dopamin, by the use of polyphenol oxidase.