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Dissertations / Theses on the topic 'Transition metal mixed chalcogenides'

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Published: 6 September 2023

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1

MONDOLONI, CHRISTIAN. "Contribution a l'etude de la valence anormale de l'ytterbium et du thulium dans yb : :(1-x)tm::(x)se et yb::(1-y)tm::(y)s." Paris 7, 1988. http://www.theses.fr/1988PA077122.

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Etude experimentale de l'instabilite de la valence des atomes de tm en fonction de la concentration dans les composes du titre. On mesure la valence des atomes de tm par susceptibilite magnetique et absorption rx, et on met en evidence une divergence de resultats par ces deux methodes. On met en evidence une transition metal-semiconducteur pour x=0,84, un ordre antiferromagnetique a 1,5 k, une magnetoresistivite negative. L'etude des sulfures amene a interpreter les proprietes de transport dans le domaine y >ou= 0,08 pour t>15 k par l'effet kondo

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2

Shaw, Graham Andrew. "Solvent mediated synthesis of metal chalcogenides." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326065.

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3

Nahai-Williamson, Paul. "Tuning ordered states in transition metal chalcogenide systems." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609901.

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4

Pickup, David M. "The structure and characterisation of amorphous transition-metal chalcogenides." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308039.

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5

Berretil, Slimane. "Proprietes electroniques des semi-conducteurs magnetiques gamo : :(4)s::(8), gamo::(4)se::(8), gamo::(4)se::(4)te::(4) et ganb::(4)s::(8)." Paris 6, 1987. http://www.theses.fr/1987PA066262.

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Etudes effectuees en vue de preciser la nature des electrons qui participent ala conduction et au magnetisme de ces composes. Les composes, caracterises par la presence d'amas tetraedriques des ions metalliques mo et nb dans les bas etats d'oxydation, revelent des proprietes de magnetisme itinerant repondant au modele de stoner-wohlfarth avec les densites d'etats les plus elevees observees dans des composes intermetalliques 3d ou 4d. La rpe a confirme que les raies observees correspondant aux ions metalliques dans un etat s = 3/2 (ions mo**(3+) et nb**(3+)); leur elargissement est d'origine dipolaire retrecie par echange et les valeurs des integrales d'echange obtenues sont en bon accord avec celles obtenues a partir des temperatures de curie

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6

Nakanishi, Makoto. "Study of magnetic ordering of vanadium in layered transition metal chalcogenides." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136959.

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7

Zhu, Bairen, and 朱柏仁. "Optical study on two dimensional transition metal dichalcogenides." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208045.

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Atomically thin group-VI transition metal dichalcogenides (TMDC) has been emerging as a family of intrinsic 2-dimensional (2D) crystals with a sizeable bandgap in the visible and near infrared range, satisfying numerous requirements for ultimate electronics and optoelectronics. This intrinsic 2D crystal also provides a perfect platform for physics study in 2D semiconductors. The characteristic inversion symmetry breaking presented in monolayer TMDCs leads to non-zero but contrasting Berry curvatures and orbital magnetic moments at K/K’ valleys located at the corners of the first Brillouin zone. These features provide an opportunity to manipulate electrons’ additional internal degrees of freedom, namely the valley degree of freedom, making monolayer TMDC a promising candidate for the conceptual valleytronics. Besides, the strong spin-orbit interactions and the subsequent spin-valley coupling demonstrated in 2D TMDCs open potential new routes towards quantum manipulation. In this thesis, I give a brief review on the background and our progress of the physics study in 2D TMDCs (MoS2, WS2) via optical spectroscopy. Particularly, our experimental approach on the excitonic effect, valley dependent circular dichroism, and the spin-valley coupling in monolayer and bilayer TMDCs are elaborated in individual chapters.
published_or_final_version
Physics
Doctoral
Doctor of Philosophy

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8

Tsang, Ka-yi, and 曾家懿. "Two dimensional transition metal dichalcogenides grown by chemical vapor deposition." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/212604.

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An atomically thin film of semiconducting transition metal dichalcogenides (TMDCs) is emerging as a class of key materials in chemistry and physics due to their remarkable chemical and electronic properties. The TMDCs are layered materials with weak out-of-plane van der Waals (vdW) interaction and strong in-plane covalent bonding enabling scalable exfoliation into two-dimensional (2D) layers of atomic thickness. The growth techniques to prepare these 2D TMDC materials in high yield and large scale with high crystallinity have attracted intensive attention recently because of the new properties and potentials in nano-elctronic, optoelectronic, spintronic and valleytronic applications. In this thesis, I develop methods for the chemical synthesis of 2D TMDCs films. The relevant growth mechanism and material characteristics of these films are also investigated. Molybdenum disulfide (MoS2) is synthesized by using molybdenum trioxide (MoO3) and sulfur (S) powder as the precursor. The films are formed on substrate pre-treated with reduced graphene oxide as the catalyst. However, this method cannot be extended to other TMDC materials such as molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) because reduced graphene oxide (rGO) reacts with selenium to form alloy materials rather than TMDC films. At the same time, the conversion of MoO3 to MoSe2 or that of tungsten trioxide (WO3) to WSe2 without the assistance of hydrogen in the chemical reaction is not thermodynamically feasible because the oxygen in the metal oxide cannot be replaced by selenium due to lower reactivity of the latter. On the other hand, I demonstrate that MoSe2 film can be synthesized directly by using MoSe2 and Se powder. Furthermore, the method of sulfurization or selenization of pre-deposited metal film can be promising due to precise thickness/size controls. Finally, some perspectives on the engineering challenges and fabrication methods of this family of materials will be given.
published_or_final_version
Physics
Master
Master of Philosophy

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9

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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10

Eaglesham, D. J. "Charge density waves and their phase transitions in the transition metal chalcogenides." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375017.

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11

Li, Tianyang. "Synthesis and Characterization of Atomic Scale Derivatives and Clusters of Transition Metal Chalcogenides." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460839448.

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12

WANG, MENGJIAO. "Colloidal Synthesis of Transition Metal Chalcogenides and Their Applications in Electrocatalytic Water Splitting." Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/941181.

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13

Jürgensen, Lasse [Verfasser]. "Thin Films of Transition Metal Chalcogenides: Novel Molecular Pathways and Catalytic Applications / Lasse Jürgensen." München : Verlag Dr. Hut, 2021. http://d-nb.info/1232846740/34.

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14

Lo, Wing-yin, and 盧詠妍. "Syntheses, characterization and emission studies of luminescent homo-and heterometallic clusters based on coinage metal alkynyl andchalcogenide core." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31245791.

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15

Gatuna, Ngigi wa. "Intrinsic vacancy chalcogenides as dilute magnetic semiconductors : theoretical investigation of transition-metal doped gallium selenide /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10595.

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16

Guo, G. Y. "Study of the electronic structures of layer-structure transition metal chalcogenides and their intercalation complexes." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233953.

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In this thesis, we present results of studies of the electronic band structures and related electronic properties of some layered transition metal chalcogenides and their intercalation complexes. The materials investigated include group VIIc transition metal dichalcogenides, and 2H-TaS₂ and its lithium-, lead-, and tin-intercalated complexes, as well as dihafnium sulphide and selenide. Both experimental measurements and theoretical elect'onic band structure calculations have been carried out. The types of measurements conducted consist of reflectivity measurements in the energy range from 0.5 eV to 4.5 eV using the home-made reflectivity spectrometer, and electron energy loss measurements in the energy range up to 100 eV using the scanning transmission electron microscope as well as some characterization experiments (structural, chemical composition and thermal properties). The experimental investigations were restricted to the layered group VIIc metal dichalcogenides. All the electronic band structures are calculated using the linearized muffin-tin orbital (LMTO) method, and are reported for the first time except PdTe₂ and 2H-TaS₂. The obtained electronic band structures for the Ni-group metal dichalcogenides, and the semiconductor-metal shift in progression from PtS₂ through PtSe₂ to PtTe₂ are discussed in terms of the binding energies of the atomic valence orbitals of the constituent atoms, the local coordination of the metal atoms and the symmetry of the crystals as well as the charge transfer effects. A superlattice structural phase transition is proposed for PtSe₂, which may possibly explain the anomaly observed in the previous transport measurement. The previous photoemission spectra from NiTe₂, PdTe₂ and PtTe₂, and dHvA measurement on PdTe₂ are compared with their band structures in details, and a good agreement is found. Other available experimental data including the previous transport, optical and magnetic susceptibility measurements as well as the reflectivity and electron energy loss spectra measured in this work are also discussed in terms of these electronic structures. The band structure calculations for dihafnium chalcogenides predict that these materials are metals. They also suggest that there is a strong bonding between Hf atoms in the adjacent layers, thus giving rise to the rigidity in the c-direction which may preclude the intercalation of these materials. The results for 2H-TaS₂ and its intercalation complexes show that the rigid band model is essentially correct for 2H-LiTaS₂ but is an oversimplication for the post-transition metal intercalation compounds. Changes in the electronic structure upon intercalation are discussed in terms of the intercalant-host charge transfer and the hybridisation between the host states and the intercalation valence orbitals. Electrical conduction in 2H-PbTaS₂ and SnTaS₂ is found to be largely due to the p-valence electrons from the intercalant Pb (Sn) layers, resulting in the considerable increase in the superconducting transition temperature following intercalation. The results are also compared with the observed optical and transport properties and a broad agreement is found. The band structures and the electronic properties of other layered transition metal dichalcogenides and their intercalation complexes, as well as the band structure calculation techniques for the layered compounds are also reviewed in this thesis.

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17

Whitton, Alan John. "Preparation and characterisation of mixed bismuth-transition metal clusters." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293876.

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18

Chung, Simon S. M. "Transition metal complexes of new mixed donor tridentate ligands." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367415.

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19

Bull, Craig Lawrence. "Structure-property relationships of some mixed transition metal perovskites." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417932.

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20

Forder, Robin James. "Transition metal complexes of phosphine and mixed phosphathia ligands." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243129.

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21

Koeckerling, Martin Dr rer nat. "Über metallreiche Halogenide und Chalkogenide früher Übergangsmetalle - Metal-rich halides and chalcogenides of early transition elements." Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-09112001-094019/.

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This habilitation thesis describes the syntheses and characterizations of mostly new metal-rich cluster compounds of early transition elements. It is devided into 4 parts. The first part describes the syntheses and solid-state X-ray structures of a total of 14 mixed-halide (iodide-chloride) zirconium cluster phases, which crystallize in 9 different (some novel) structure types. All these cluster phases contain octahedral Zr6Z-units that are centered by an interstitial atom Z. Phase widths and relations between the differend structure types are discussed. The second part deals with molecular (soluble) zirconium cluster phases which are excised from solid-state precursors. It is shown that liquid mixtures of 1,3-dialkylimidazolium bromide and AlBr3 as well as molten 18-crown-6 are useful solvents for molecular zirconium cluster compounds. The syntheses and single crystal X-ray structures of 3 new materials are detailed. Furthermore, from the reaction of an iron containing Zr-cluster phase with KSCN crystals have been obtained from which a single crystal X-ray structure analysis shows that they contain a high symmetry Fe-cubane cluster. The third part of this thesis is concerned with theoretical investigations (Extended-Hckel band structure calculations) of a series of monoclinic phases which contain double-octahedral chains of rare earth metal clusters of the general formula RE3I3Z (RE = rare-earth metal atoms). The results of the electronic band structure calculations show that the observed structural variations within this series depend largely on the difference of the orbital energies of the rare earth metals and the interstitials. In the last part the phase pure synthesis of Nb21S8 and measurements of physical properties (electrical conductivity and magnetical susceptibility) as well as results from electronic band structure calculations (LMTO) are described. The property measurements show that this metal rich sulfide becomes superconducting below 3.7(2) K. The results from the electronic band structure calculations indicate the existence of an arrangement of electronic levels ("fingerprint") which favors the formation of superconducting Cooper pairs.

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22

Taylor, J. M. C. "The structure and properties of some mixed transition metal oxides." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382735.

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23

Lee, Yui-bing, and 李蕊冰. "The chemistry of osmium-silver and osmium-iridium mixed-metalclusters." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40987632.

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24

Lee, Yui-bing. "The chemistry of osmium-silver and osmium-iridium mixed-metal clusters." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40987632.

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25

Qasim, Ilyas. "Structural and Electronic Phase Transitions in Mixed Transition Metal Perovskite Oxides." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10029.

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The reported multiferroic perovskite series Sr1-xAxTi1/2Mn1/2O3 has been the subject of numerous structural studies, without reaching consensus. In the current work, the cubic Pm3 ̅m is confirmed for end member SrTi1/2Mn1/2O3 in the Sr1-xAxTi1/2Mn1/2O3 ( A= Ca, La; 0 ≤ x ≤ 1) series. The Pm3 ̅m  I4/mcm  Pbnm structural evolution was observed with increased doping level of Ca. A cubic Pm3 ̅m  rhombohedral R3 ̅c transition occurred when La is substituted instead of Ca. Interesting magnetic behaviours were observed and the major contribution to this was concluded to be the mixed Mn4+/Mn3+ ratio. Ru and Ir have almost identical ionic radii and behave similarly in many ways. Remarkably the structure and properties of SrRuO3 and SrIrO3 are different. The current study revealed that the divalent transition metal doped materials of the type SrR1-xMxO3 (R = Ru, Ir, and M = 3d transition metals) are isostructural. This was achieved by the synthesis of a number of new materials of the type SrIr1-xMxO3. Therefore, these two series are comparatively described in the thesis. The structure and physical properties of the iron doped series SrIr1-xFexO3 are found to be different from those of the divalent doped ones, and this was even true for Ru analogues. Therefore, Fe-doped SrRuO3 and SrIrO3, based on the results of the same level doped materials are presented in a separate chapter. In the final chapter, the impact of Cu2+ doping on the structure and electronic properties of LaCrO3 is described. In order to understand structure property relationships, all the materials structurally characterised have had magnetic and resistivity measurements conducted. Special attention is given to realise the correlations between structure, magnetism, and conductivity.

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26

Takeiri, Fumitaka. "Topochemical and High-Pressure Routes to Synthesize Transition-Metal Mixed Anion Oxides." Kyoto University, 2017. http://hdl.handle.net/2433/228237.

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27

Jong, Howard. "Late transition metal complexes incorporating hemilabile mixed-donor N-heterocyclic carbene ligands." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23473.

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The discovery of N-heterocyclic carbenes (NHC) has dramatically affected the world of catalysis. Their inherent properties that make them excellent auxiliary ligands for catalytic processes have countless laboratories worldwide probing and exploiting every notable feature they possess. However, while there is no shortage of attention in this field of research, there has been considerably less interest in NHCs with an ability chelate to metals via a mixed-donor ligand architecture. Thus, this thesis describes the synthesis and application of a ligand set comprised of bidentate mixed-donor NHC ligands. The ligands prepared all contain a mesitylimidazol-2-ylidene core unit, but incorporate different donor-functionalized tethers. These mixed-donor NHC ligands are synthesized by using a strong base, such as KN(SiMe₃)₂, to deprotonate the imidazolium salt precursors. This strategy was used to effectively prepare 1-mesityl-3-(2-(mesitylamino)ethyl)imidazol-2-ylidene, Mes[CNH] and 1-mesityl-3-(2-aminoethyl)imidazol-2-ylidene, Mes[CNH₂]. Mes[CNH] was found to be a convenient proligand for the synthesis of various M-NHC (M = Rh, Ir, Ru, Pd, Ni, Fe, Ag, Li) compounds. These Mes[CNH]-M complexes demonstrated the hemilabile character of the Mes[CNH] ligand forming complexes that incorporated either a coordinated or uncoordinated amino tether. Mes[CNH]M(diene)Cl, Mes[CN]M(diene) and [Mes[CNH]M(diene)]BF₄(M = Rh, Ir; diene = 1,5-cyclooctadiene, 2,5-norbornadiene) were synthesized and investigated for their ability to perform hydrogenation and hydrosilylation reactions with various substrates. Mes[CNH]Ru(=CHPh)(PCy₃)Cl₂, Mes[CNH]Ru(=CHPh)(py)Cl₂ (py = pyridine) and Mes[CNH]Ru(=CHPh)(PMe₃)Cl₂ were also synthesized and fully characterized. The activity of the former two Ru complexes was studied for their ability to catalyze ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROMP) reactions. In addition, the phosphine dissociation rate of Mes[CNH]Ru(=CHPh)(PCy₃)Cl₂ was measured via magnetization transfer experiments and compared to other known Ru-benzylidene analogues. In addition to the amino-tethered NHC proligands, a phosphine analogue Mes[CP] was prepared and its reactivity with late transition metal complexes was investigated. While the free NHC-phosphine species could not be isolated, deprotonation of both the iminium and phosphine protons followed by the addition of [M(COD)Cl]₂ (M = Rh, Ir) yields Mes[CP]M(COD), which incorporates a bidentate NHC-phosphide ligand. Mes[CP]Ir(COD) was then investigated for its ability to perform hydrogenation and benchmarked to its Mes[CN]Ir(COD) analogue.

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28

Stahl, Juliane [Verfasser], and Dirk [Akademischer Betreuer] Johrendt. "Low-dimensional transition metal chalcogenides : Synthesis and characterization of beta-FeSe- and Fe3GeTe2-related structures / Juliane Stahl ; Betreuer: Dirk Johrendt." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1204005559/34.

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29

Harani, R. "Studies of electronic properties of mixed transition metal oxide and lanthanide phosphate glasses." Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353991.

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30

Kramer, Alan Richard. "Surfaces and Epitaxial Films of Corundum-Structured Mixed Metal Oxides." Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7418.

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Throughout the last half century of materials science, significant motivations came from, and still do, the industrial applications of these materials. Whether it is electronic, thermal, tribological or chemical in nature, the study of metals, semiconductors and insulators eventually reveals that the surface plays a significant part in the properties of these materials. Understanding metal terminations reveals often that an oxide is the stable state of the metallic surface in an ambient atmosphere and the ability to predict and control these oxides has led to significant strides forward in not just the metallic bulk but the oxide as well. Here we add to the understanding of the class of materials known as transition metal oxides by focusing on the structural and chemical nature of their surfaces. Vanadia, chromia and a new mixed metal oxide, VTiO3, all of which form the corundum structure and have physical properties that need further study. Specifically, Cr2O3 has been at the center of much debate over how oxygen chemical potential influences surface terminations and top layer relaxation. Chromia is a wide band gap (~3.4eV) insulator with substantial ligand field interaction and measurements of the 3d states reveal these states split to t2g and eg– consistent with the distorted octahedral. V2O3 is known to be a Mott insulator and paramagnetic, properties that can be modified through dopants, stoichiometry and strain. In this work, solid solutions of V2O3 and Ti2O3 are studied. VTiO3, has been synthesized in a corundum – like structure by epitaxial growth on an isostructural α-Al2O3 substrate. Section I offers a review of corundum like transition metal oxides and their surface properties and motivations of continued research. In section II we describe in detail, the critical components of PLD thin film growth and in the next section a review of the pertinent characterization techniques utilized in the process. Finally, the results are presented of the study of two transition metal oxide structures namely: 1) Novel VTiO3 in a corundum structure has been grown via Pulsed Laser Deposition – Molecular Beam Epitaxy on a single crystal Al2O3(0001) substrate. The sapphire substrate with modest lattice mismatch was utilized in an effort to compel heteroepitaxial growth of the VTiO3 film. Confirmation of the films structure & chemical state were performed by X-Ray diffraction, Transmission Electron Microscopy (HR), X-Ray Photo-electron Diffraction, Ultra-Violet Photo-Electron Diffraction and Reflection High Energy Electron expected that the metal ions exist in a 3+ charge state. While XPS clearly points to a V3+ charge state and this suggests that Ti should as well, however there is also a strong Ti4+ component present. EELS spectra support the existence of a mixed state Ti3+ & 4+. Broadening of the valance band edge as revealed by UPS spectra indicate that the 3d orbitals are occupied and that the a1g molecular states are occupied. The conflict in diffraction data supporting corundum and PES/EELS data suggesting a mixed state implies that additional final state effects are present and/or an oxygen rich structure. 2) Additionally, corundum like Chromium(III) Oxide is formed on a Cr(110) surface and characterized with X-Ray Photoelectron Diffraction, Low Energy Electron Diffraction and XPS for the purpose of characterizing surface termination and terminating layer relaxation. Comparison of the XPD diffraction data with known and previously discussed terminations reveal the as grown film does not conform. Consequently, we propose a new, stoichiometric termination with oxygen termination and 1st layer chromium interstitials. Atop this structure was grown an ultra-thin film of V2O3 by vanadium e-beam evaporation in background oxygen. This final structure supports the previously proposed vanadyl structured surface

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31

Hashiguchi, Ryota. "Studies on Polynuclear Metal Complexes and Low-Dimensional Mixed-Valence Halogen-Bridged Transition Metal Complexes Based on them." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225426.

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32

Macpherson, Brendan P. "Discrete cyano-bridged mixed valence systems /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17778.pdf.

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33

Belke, Christopher [Verfasser]. "Untersuchung von Dünnschicht-Übergangsmetall-Chalkogeniden hinsichtlich ihrer elektrischen Eigenschaften : Investigation of thin film transition metal chalcogenides regarding their electrical properties / Christopher Belke." Hannover : Gottfried Wilhelm Leibniz Universität, 2021. http://d-nb.info/1230550666/34.

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34

Yakushev, I. A., N. Y. Kozitsyna, O. N. Kondratyeva, M. N. Vargaftik, and I. I. Moiseev. "Mixed-Metal Palladium(II) Complexes: a Way from Heterometallic Carboxylates to Bimetallic Nanoparticles." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35239.

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The paper describes some chemical transformations of the mixed-metal palladium (II) complexes, including interactions of binuclear complexes with pyridine, 1,10-phenanthroline and bipyridine; also described thermal and reductive transformations of some binuclear and pentanuclear nitrogen-containing complexes, in particular red-ox transformations in reductive media to yield mixed-metal nanomaterials. For this nanomaterials and nanoalloys also provided HREM and TEM investigations. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35239

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35

Ghorbani-Asl, Mahdi [Verfasser], Thomas [Akademischer Betreuer] Heine, Ulrich [Akademischer Betreuer] Kleinekathöfer, Thomas [Akademischer Betreuer] Frauenheim, and Agnieszka [Akademischer Betreuer] Kuc. "Electronic transport through two-dimensional transition-metal chalcogenides / Mahdi Ghorbani-Asl. Betreuer: Thomas Heine. Gutachter: Thomas Heine ; Ulrich Kleinekathöfer ; Thomas Frauenheim ; Agnieszka Kuc." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2014. http://d-nb.info/1087315506/34.

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36

Otake, Ken-ichi. "Studies on the Dimensional-Extended Halogen-Bridged Mixed-Valence Transition-Metal Complexes: Neutral-Chains and Nanotubes." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217132.

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37

Lu, Xiaonan. "Effects of Transition Metal Oxide and Mixed-Network Formers on Structure and Properties of Borosilicate Glasses." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404587/.

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First, the effect of transition metal oxide (e.g., V2O5, Co2O3, etc.) on the physical properties (e.g., density, glass transition temperature (Tg), optical properties and mechanical properties) and chemical durability of a simplified borosilicate nuclear waste glass was investigated. Adding V2O5 in borosilicate nuclear waste glasses decreases the Tg, while increasing the fracture toughness and chemical durability, which benefit the future formulation of nuclear waste glasses. Second, structural study of ZrO2/SiO2 substitution in silicate/borosilicate glasses was systematically conducted by molecular dynamics (MD) simulation and the quantitative structure-property relationships (QSPR) analysis to correlate structural features with measured properties. Third, for bioactive glass formulation, mixed-network former effect of B2O3 and SiO2 on the structure, as well as the physical properties and bioactivity were studied by both experiments and MD simulation. B2O3/SiO2 substitution of 45S5 and 55S5 bioactive glasses increases the glass network connectivity, correlating well with the reduction of bioactivity tested in vitro. Lastly, the effect of optical dopants on the optimum analytical performance on atom probe tomography (APT) analysis of borosilicate glasses was explored. It was found that optical doping could be an effective way to improve data quality for APT analysis with a green laser assisted system, while laser spot size is found to be critical for optimum performance. The combined experimental and simulation approach adopted in this dissertation led to a deeper understanding of complex borosilicate glass structures and structural origins of various properties.

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38

Bouilly, Guillaume Jacques. "Synthesis and characterization of transition metal oxides and oxyhydrides using epitaxial thin films deposition." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200450.

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39

Lam, Chan-fung. "Synthesis, optical and luminescence studies of rhenium(I) diimine alkynyl complexes and their utilization as building blocks for the assembly of multinuclear and mixed-metal complexes." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B32010564.

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40

Xu, Yin. "Preparation of noble metal free mixed oxides : applications to environmental catalysis." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R070.

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Dans un contexte politique et législatif favorisant l’utilisation de métaux abondants et non toxiques, différentes classes de catalyseurs à base de métaux de transition ont été développées puis évaluées pour deux réactions de dépollution : (i) l’ozonation catalytique pour l’élimination de polluants en phase aqueuse et (ii) l’oxydation catalytique de composés organiques volatils en phase gazeuse. Les oxydes de structure type spinel AB2O4 et les pérovskites possédant la formule générale ABO3 (où A et B sont des cations métalliques) sont des candidats intéressants de par leur innocuité et leur plus faible coût comparé aux métaux de la famille du platine. Par ailleurs, les propriétés versatiles de ces oxydes mixtes, telles que les nombreuses compositions possibles et leurs états de surface associés, ont démontré leur intérêt en catalyse hétérogène. Dans la première réaction concernant les procédés d’oxydation avancés, des oxydes mixtes de structure type spinel ont été étudiés pour agir comme catalyseur de dégradation de polluants organiques (AO7 et bisphénol A). Deux compositions, CuAl2O4 et CuFe2O4, ont été identifiés comme catalyseurs actifs pour l’activation de l’ozone et du peroxymonosulfate, précurseurs d’espèce radicalaires. La combinaison du cuivre avec l'aluminium ou avec le fer s’est révélée bénéfique pour former des radicaux réactifs à partir d’ozone ou de péroxymonosulfate, améliorant nettement la dégradation des polluants visés par rapport aux oxydes simples. Dans la seconde réaction impliquant l’oxydation catalytique du formaldéhyde en phase gazeuse, des pérovskites et des oxydes de manganèse ont été évalués. Une étude sur l’enrichissement en surface du métal de transition a été réalisée soit par traitement chimique via un lavage acide du précurseur pérovskite, soit par une approche de synthèse en sous-stœchiométrie employée lors de la préparation. Au regard des résultats expérimentaux, cet enrichissement permet d’exalter les propriétés catalytiques des solides pour l’élimination du formaldéhyde à basse température. Ces performances peuvent être reliées aux effets cumulés associés à la formation d’une morphologie contenant une porosité multiple suite au traitement chimique par voie acide, à l’augmentation significative de la surface spécifique et à l’augmentation de la densité des sites redox de surface mise en évidence par le suivi du couple Mn4+/Mn3+. Enfin, la promotion du support catalytique LaMnO3 par des métaux alcalins et alcalino-terreux a été réalisée (La0.8A0.2MnO3 avec A = K, Na, Sr, Ca). Basé sur les performances catalytiques à une température donnant une conversion de 50%, le dopage au potassium s’est révélé être le plus attractif (La0.8K0.2MnO3> La0.8Na0.2MnO3> La0.8Sr0.2MnO3> LaMnO3≈ La0.8Ca0.2MnO3≈ LMO-OH ≈ LMO-Na). Des vieillissements chimiques sous conditions humides et sèches ont par conséquent été réalisés sur les meilleurs catalyseurs afin d’évaluer leur robustesse. Malgré une conservation des propriétés texturales, une désactivation graduelle des pérovskites dopées (K, Na, Sr) a été observée et reliée à une perte d’espèces actives de surface et à une réduction du degré d’oxydation moyen du manganèse
In a political and legislative context promoting the use of abundant and non-toxic metals, different classes of transition metal catalysts have been developed and evaluated for two depollution reactions: (i) catalytic ozonation or activated persulfate for the elimination of pollutants containing nitrogen in the aqueous phase and (ii) the catalytic oxidation of volatile organic compounds in the gas phase. Structural spinel oxides AB2O4 and perovskites having the general formula ABO3 (where A and B are metal cations) are interesting candidates because of their safety and lower cost compared to platinum family metals. Moreover, the versatile properties of these mixed oxides, such as the numerous possible compositions and their associated surface states, have demonstrated their interest in heterogeneous catalysis. In the first reaction concerning advanced oxidation processes, spinel type mixed oxides have been studied to act as a degradation catalyst for organic pollutants (AO7 and bisphenol A). Two compositions, CuAl2O4 and CuFe2O4, have been isolated as active catalysts for the activation of ozone and peroxymonosulphate radical precursors. The combination of copper with aluminum or iron has been found to be beneficial in forming reactive radicals from ozone or peroxymonosulphate, significantly improving the degradation of targeted pollutants compared with simple oxides. In the second reaction involving the catalytic oxidation of formaldehyde in the gas phase, the perovskites and the manganese oxides were evaluated. A study dealing with the surface enrichment of the transition metal was carried out either by chemical treatment via acid washing of the perovskite precursor, or by a sub-stoechiometric approach used during the preparation. At the light of the experimental results, this enrichment improves drastically the elimination of formaldehyde towards low temperatures. These performances can be related to the cumulative effects associated with the formation of a morphology containing a multiple porosity following the acidic chemical treatment, the significant increase of the specific surface and the increase of the density of the surface redox sites highlighted by the Mn4 + / Mn3 + couple. Finally, the promotion of the catalytic support LaMnO3 by alkali and alkaline earth metals was carried out according to different conditions (La0.8A0.2MnO3 with A = K, Na, Sr, Ca). Based on the catalytic performances at a temperature giving a conversion of 50% of formaldehyde in CO2, potassium doping proved to be the most attractive doping agent (La0.8K0.2MnO3> La0.8Na0.2MnO3> La0.8Sr0.2MnO3> LaMnO3 = La0. 8Ca0.2MnO3= LMO-OH = LMO-Na). Chemical aging under wet and dry conditions has therefore been carried out on the best catalysts to evaluate their robustness. Despite a conservation of textural properties, a gradual deactivation of the doped perovskites (K, Na, Sr) was observed and related to a loss of surface active oxygen species and a reduction in the average degree of oxidation of manganese

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41

Käß, Martina [Verfasser], and Karsten [Akademischer Betreuer] Meyer. "Late Transition Metal Complexes of Mixed NHC/Phenolate Tripodal Ligands for Small Molecule Activation / Martina Käß. Gutachter: Karsten Meyer." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/1075477379/34.

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42

Hajiyani, Hamidreza [Verfasser], Ralf [Gutachter] Drautz, and Jörg [Gutachter] Neugebauer. "Mechanical and electrochemical properties of mixed transition metal oxides in cathode materials / Hamidreza Hajiyani ; Gutachter: Ralf Drautz, Jörg Neugebauer." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1121909280/34.

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43

Lam, Chan-fung, and 林親鳳. "Synthesis, optical and luminescence studies of rhenium(I) diimine alkynyl complexes and their utilization as building blocks for theassembly of multinuclear and mixed-metal complexes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B32010564.

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44

Don, Ming-jaw. "Ligand Substitution Studies in the Tetracobalt Cluster Co₄(CO)₁₀([mu]₄-PPh₂) and Synthesis and Reactivity Studies in the Fe₂Pt and FeCo₂ Mixed-metal Clusters." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc279335/.

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The kinetics of ligand substitution for CO in Co4(CO)10(mu4-PPh2) , 1, have been investigated for the ligands P(OMe)3, P(OEt)3, PPh2H, P(0-i-Pr)3, P(n-Bu)3, PPh3, P(i-Pr)3, and PCy3 over a wide temperature range.

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45

Mondal, Sudipta [Verfasser], and Wolfgang [Akademischer Betreuer] Kaim. "Transition metal complexes with 1,2-dicarbonylhydrazine : a study on mixed-valency and non-innocent ligand behaviour / Sudipta Mondal ; Betreuer: Wolfgang Kaim." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2018. http://d-nb.info/1169653715/34.

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46

Zamudio-Bayer, Vicente [Verfasser], Thomas [Akademischer Betreuer] Möller, Issendorff Bernd [Akademischer Betreuer] von, and Tobias [Akademischer Betreuer] Lau. "Magnetic properties of pure and mixed 3d 5 transition metal clusters / Vicente Zamudio-Bayer. Gutachter: Thomas Möller ; Bernd von Issendorff ; Tobias Lau." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/106738555X/34.

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47

Kitagawa, Hiroshi. "Systematic Studies on the Mixed-Valence States of Perovskite-Type Transition-Metal ComplexesCs[2]Au[2]X[6](X=Cl,Br,I)." 京都大学 (Kyoto University), 1992. http://hdl.handle.net/2433/168823.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第4980号
理博第1377号
新制||理||769(附属図書館)
UT51-92-J27
京都大学大学院理学研究科化学専攻
(主査)教授齋藤軍治, 教授小菅皓二, 教授新庄輝也
学位規則第4条第1項該当

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48

Baker, Schuyler Denton. "Eco-friendly driven remediation of the indoor air environment: the synthesis of novel transition metal doped titania/silica aerogels for degradation of volatile and semi-volatile organic compounds." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13348.

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Master of Science
Department of Chemistry
Kenneth Klabunde
Remediation of the indoor environment led to the development of novel catalysts which can absorb light in the visible range. These catalysts were prepared using the wet chemistry method known as sol-gel chemistry because preparation via sol-gel provides a homogeneous gel formation, which can be treated via supercritical drying to produce an aerogel. These aerogels have been found to have high surface areas when a combination of titania/silica is used. The increase in surface area has been shown to enhance the activity of the catalysts. Mixed metal oxide systems were prepared using titanium isopropoxide and tetraethyl orthosilicate to yield a 1:1 system of titania/silica (TiO2/SiO2). These systems were doped during the initial synthesis with transition metals (Mn or Co) to create mixed metal oxide systems which absorb light in the visible light range. These materials were assessed for potential as heterogeneous catalysts via gas-solid phase reactions with acetaldehyde. Degradation of acetaldehyde as well as the formation of CO2 was monitored via gas chromatography-mass spectrometery. To increase the activity, visible light was introduced to the system. Experiments have shown that a 10 mol % manganese doped titania/silica system, in the presence of light, can degrade acetaldehyde. The cobalt doped counterpart showed dark activity in the presence of acetaldehyde resulting in the formation of CO2 without the addition of visible light. In the hope of increasing surface area a mixed solvent (toluene/methanol) synthesis procedure was applied to the manganese doped catalyst. The resulting materials were of a low surface area but showed a significant increase in degradation of acetaldehyde. Examination of the interactions between mixed metal oxide systems and semivolatile organic compounds (SVOCs) was studied. The pollutant, triphenyl phosphate, was dissolved in n-pentane and exposed to 10 mg of a given catalyst. These reactions were monitored using UVVis. All systems but the manganese doped titania/silica system resulted in the observation of no activity with triphenyl phosphate. The manganese doped catalyst shown a peculiar activity, the increase in absorbance of the triphenyl phosphate peaks as well as the formation of a new peak.

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49

Lima, Bruno Sanches de. "Crescimento de monocristais e investigação experimental de propriedades físicas de calcogenetos de nióbio." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/97/97135/tde-03122018-164756/.

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Recentemente foi descoberto que diversos calcogenetos de metais de transição podem ter o estado charge density waves (CDW) suprimido a partir de pressão hidrostática e dopagens, e, por conseguinte, o estado supercondutor emerge. Nesse contexto, este trabalho apresenta um estudo sistemático de propriedades físicas de amostras poli e monocristalinas de dois compostos do sistema Nb-Te, NbTe2 e NbTe4. Com relação ao composto NbTe2, os resultados aqui apresentados demonstram que esse composto é mais um exemplo de material que exibe ambos os estados a pressão atmosférica e sem dopagens. No que tange as propriedades do NbTe4, este trabalho demonstra que amostras deficientes em telúrio tem a anomalia na curva de resistividade elétrica relacionada a formação do estado CDW amplificada e, a deficiência em telúrio é também capaz de fazer emergir supercondutividade em 5.5 K. Este trabalho também sugere algumas mudanças no diagrama de equilíbrio de fases Nb-Te publicado na base de dados da sociedade americana de metalurgia (ASM). As fases Nb5Te4 e Nb3Te4 foram identificadas como sendo fases de altas temperaturas que são formadas a partir de reações eutetóides. Além do mais, nossos resultados demonstram que a região entre as fases NbTe2 e NbTe4 consiste, na verdade, de uma região bifásica. Durante a realização deste trabalho, outro composto foi investigado, o NiTe2. Nesse composto, nossos resultados demonstram que a intercalação de Ti faz emergir um estado supercondutor em 4.5 K e cuja temperatura de transição parece insensível a pressão hidrostática. Cálculos de estrutura de bandas sugerem fortemente que o composto NiTe2 intercalado com Ti pode ser mais um exemplo de supercondutor com aspectos topológicos em sua superfície de Fermi.
Recently was demonstrated that it is possible to suppress the charge density waves (CDW) ground states while, simultaneously, a superconductor state emerges in several transition metal chalcogenides (TMC), by means of hydrostatic pressure or chemical doping. Within this context, this work presents a systematic study on physical properties of two Nb chalcogenides, NbTe2 and NbTe4. Our results demonstrate that NbTe2 is another example of a TMC which exhibit both stabilities at atmospheric pressure and without doping. Regarding the physical properties of NbTe4, we have demonstrated that Te deficiency increases significantly the anomaly in the electrical resistivity as function of temperature behavior related with the CDW formation. At the same time, Te deficiency can also cause a SC state to emerge at 5.5 K. This work also presents a review of the binary phase diagram, Nb-Te, and some changes are proposed. Nb5Te4 and Nb3Te4 were identified as high temperature phases originated from eutectoid reactions. Furthermore, our results demonstrated that the region between the phases NbTe2 and NbTe4 are, in fact, a two-phase region, differently from what is proposed in the actual version of the phase diagram. Also, during this work, another chalcogenide was investigated, NiTe2. Our results demonstrate that Ti can be intercalted between the Van der Waals gaps of the structure and consequently a superconductor state emerges at 4.5 K. The critical temperature is found to be insensitive to hydrostatic pressure. Band structure strongly suggests that NiTe2 could be another example of a superconductor with topological aspects in its Fermi surface.

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Bacher, Patrice. "Etude du profil des raies de diffraction neutronique en temps de vol utilisant un obturateur statistique : application à l'étude d'oxynitrures de structure tétraèdrique ou de type pérovskite." Grenoble 1, 1987. http://www.theses.fr/1987GRE10035.

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Application de l'etude du titre a deux grandes famille structurales: (1) les structures tetraedriques derivant de cele de la wuertzite (li::(1,33)ge::(1,67)on::(2); zn::(1,231)ge::(0,689)o::(0,782)n::(1,218); kgeon), (2) les structures de type perovskite (batao::(2)n, banbo::(2)n, lawo::(0,6)n::(2,4))

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