Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 356 for “"Metal oxides"”.
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Novel Transition-Metal Oxides Under Pressure
Transition-metal oxides have been the focus of multiple experimental and theoretical research efforts because of their versatility and applicability to new technology. These characteristics mostly owe to our ability to adjust valence states and crystal fields, among others, by fine-tuning …
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Structural studies of layered transition metal oxides
A number of transition metal oxide materials, both new and previously reported, have been<br/>synthesised, their structures based on the n = 2 Ruddlesden-Popper layered perovskites. Their<br/>structures were determined through Rietveld refinement against X-ray and neutron powder<br/>diffraction, …
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Lithium intercalation reactions with transition metal oxides
An investigation of several lithium transition metal oxide systems has been undertaken with the aim of synthesising an optimised LiM0₂ compound (M = Mn, Co or Co/Ni mixtures) for application as a cathode in rechargeab1e lithium batteries. Attention has been focused on systems which show promise for …
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Metalorganic chemical vapor deposition of metal oxides
… disks, and Pt/Ti/SiO₂/Si substrates by hot wall metalorganic chemical vapor deposition (MOCVD). Bis(cyclopentadienyl)ruthenium [Ru(C₅H₅)₂], zirconium tetramethylheptanedione [Zr(thd)₄], triphenylbismuth [Bi(C₆H₅)₃], and titanium ethoxide [Ti(C₂H₅O)₄] were used as precursors. MOCVD RuO₂ film …
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The low-temperature formation of mixed-metal oxides
This thesis describes a new route to lithium molybdate, Li₂MoO₄, which involves grinding together LiOH·H₂O and MoO₃ in air at room temperature. X-ray powder diffraction data show that the formation of highly crystalline Li₂MoO₄ is largely complete after 10 min, and that this product crystallises …
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Metal oxides for efficient infrared to visible upconversion
… for near-infrared to visible upconversion. Being oxides, these materials have good chemical, thermal and mechanical properties. A variety of dopants, including Yb3+, Er3+, Ho3+ and Tm3+, were embedded in the host lattice, resulting in bright red, green, blue and white light emissions under 980 nm …
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Electrode materials for the electrolysis of metal oxides
… at low voltage, consumption of current by metal oxide formation, and ease of surface oxide electro-stripping. Conductivity during electrolytic oxidation is observable as current density maximization at high voltages. While carbon, tungsten, and platinum formed surface oxides, iridium …
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Synthesis and catalytic application of functional transition metal oxides
… economic combustion catalysts such as transition metals oxides (TMOs), using an elaborated Pulsed Spray Evaporation Chemical Vapor Deposition (PSE-CVD) approach and improved understanding of their behavior. Catalysts based on TMOs were successfully synthesized by PSE-CVD. Comprehensive …
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Transition Metal Oxides for Cathode of Li-ion Battery
Layered transition metal oxides are used as cathode materials in Li-ion batteries particularly in those used in the automobile industry. With growing demands for high energy supply for practical applications, Ni -rich cathodes have become a popular option due to their high theoretical capacity; …
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Atomic layer deposition of metal oxides for photovoltaic applications
Organic-inorganic halide perovskite solar cells have gained a lot of traction in recent years due to their high power conversion efficiencies (PCE), >20%, tunable band gap and low fabrication costs. However, as the maximum theoretical efficiency outlined by the Shockley-Quiesser model for a …
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Surface-mediated mechanisms for defect engineering in metal oxides
… interstitial atoms influence the performance of metal oxides in gas sensing, electronics, photonics and solar-induced photochemistry for fuel production and environmental cleanup. Controlling these aspects of defect behavior has become increasingly important in nanoscale applications, where …
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Models for transition metal oxides and for protein design
… structure and total energy of transition metal oxides. We demonstrate that the LDA+U method, in which localized d electrons are treated with a Hubbard-like model, gives considerably better predictions in band gap, magnetization, lattice constants, redox potential, mixing energy and other …
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Impurities in Antiferromagnetic Transition-metal Oxides – Symmetry and Optical Transitions
The study of antiferromagnetic transition-metal oxides is an extremely active area in the physical sciences, where condensed matter physics, inorganic chemistry, and materials science blend together. The sheer number of potential commercial applications is staggering, but much of the fundamental …
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Solvent-free Knoevenagel condensation over supported mixed metal oxides catalysts
Submitted in the fulfilment of the requirement for the Master's Degree in Chemistry, Durban University of Technology, Durban, South Africa, 2017.
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Investigation of structural changes in vanadium containing transition metal oxides
We have completed an experiment to obtain diffuse scattering data for use in a comprehensive study of the local-structure changes as a function of molybdenum composition and have made large strides in interpreting some of the major changes found in this study. For these experiments, single crystals …
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Synthesis and characterisation of metal oxides and metal doped variants
… <br></br><br></br>The unit cell size of the metal-doped ferrite, Fe<sub>3-x</sub>Sn<sub>x</sub>O<sub>4</sub>, 0 < x < 0.4, has been shown by X-ray powder diffraction(XRD) to increase linearly as tin content increases. Extended X-ray Absorption Fine Structure (EXAFS) show that the …
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DEVELOPMENT OF NANO-STRUCTURED METAL OXIDES/GRAPHENE FOR ENERGY APPLICATIONS
… provides a new avenue to create nanostructured metal oxide/graphene hybrid with improved properties, as long as they can be synthesized via the sol-gel process or by a reaction in solutions.</p>
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DEVELOPMENT OF NANO-STRUCTURED METAL OXIDES/GRAPHENE FOR ENERGY APPLICATIONS
… provides a new avenue to create nanostructured metal oxide/graphene hybrid with improved properties, as long as they can be synthesized via the sol-gel process or by a reaction in solutions.
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