Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 82-83).

Thesis (Ph.D.)--University of Tulsa, 1995. / Includes bibliographical references (leaves 197-214).

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 200-207). Also available online in ProQuest, free to University of Oregon users.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 111-119).

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 17, 2007) Vita. n following parenthesis in formula (LaTiO₃) should be subscript. Includes bibliographical references.

Contents: a. The oxidation of metals by atomic and molecular oxygen -- b. Calculation of the heats of formation of point defects in some transition metal oxides.

The crystal growth conditions of compounds of the series Srn+1IrnO3n+1 (n=1, 2 and ∞) are investigated. It was found that the ratio of IrO2:SrCO3 in the starting mixture is the most important variable in determining the phase formed. Good quality samples of Sr3Ir2O7 were found to have a sharp change in gradient at the Néel temperature of 287.5 K and no secondary T* transition between 230 K and 260 K. All crystals of Sr3Ir2O7 grown were found to be heavily oxygen deficient by EPMA regardless of the crystal growth conditions used with an average stoichiometry of Sr2:87Ir2O6:27. Adding more electrons via replacing strontium with lanthanum causes (Sr(1-x)Lax)3Ir2O7 to become metallic by x=0.072, which also fully quenches the long-range antiferromagnetic order. Heat capacity and resistivity measurements show that metallic (Sr(1-x)Lax)3Ir2O7 is a weakly correlated Fermi-liquid metal. Given that there are only subtle changes to the structure upon lanthanum doping, the metal-insulator transition is a result of electron doping rather than structural distortions. No structural phase transitions were found up to a temperature of 800°C and no additional evidence was found to support the Bbcb space group model of the structure of Sr3Ir2O7. Using crystals five times better in quality than those reported in the literature, SrIrO3 was found to be a Fermi-liquid metal, rather than a non-Fermi liquid metal as previously reported, and no superconductivity was found down to temperatures of 20 mK. A known Pt(III) compound, CaPt2O4, was found to be a weakly correlated metal down to 2 K and a novel Pt(III) based compound, K2CaPt3-δ O6 (δ ≈ 0.4), was discovered. K2CaPt3δ-O6 has a structure consisting of monolayers of edge-sharing PtO6 octahedra separated by layers of ordered K+ and Ca2+ ions in a 2:1 ratio. The structure of K2CaPt3-δO6 was found to be flexible to doping with copper, causing the magnetic properties to change from temperature independent to paramagnetic.

The development of energy storage and conversion techniques with high efficiency and power density is of great importance for the sustainable development of our green world. Li-O₂ batteries with high theoretical energy density has attracted extensive attention. However there are still many issues waiting to be solved, such as low stability of cathode catalyst, as well as the deactivation of cathode by H₂O and CO₂ from air. Reversible solid oxide fuel cells can be used for electricity production by SOFCs and fuel production (H₂ and O₂) by SOECs. Thus, oxygen storage materials can bridge Li-O₂ batteries and reversible SOFCs with the purpose of increasing the whole efficiency of the system. The discovery of oxygen storage materials with reversible oxygen release/storage behaviours and high oxygen storage capacities dependent on temperature or oxygen partial pressures (e.g., inert and oxidation gases) still needs further research. The work in this thesis mainly focuses on the preparation of transition-metal based oxides (such as perovskite oxides, brownmillerite-type oxides, layered-perovskite oxides, coated β-MnO₂ nanorods, transition-metal doped CeO₂ nanocrystals) as oxygen storage materials and their energy-related applications, seeking to discover the principles for oxygen storage/release properties and their performance in energy conversion and storage applications. The prepared materials included nanostructured and bulk materials via various synthesis methods, including citrate-modified evaporation-induced self-assembly method, hydrothermal method, pechini method, as well as solid state method. This work investigated the oxygen storage capacities of several crystal structure types oxides based on transition-metals. Nanostructured La₀.₆Ca₀.₄Fe₁₋ₓCoₓO[sub](3-δ) and La₀.₆Ca₀.₄Mn₁₋ₓFeₓO[sub](3-δ) exhibit high oxygen storage capacities and stability under reductive 5%H₂/Ar, but the oxygen-storage content under inert argon is low, just about 0.2 wt%. Brownmillerite-type Ca₂AlMnO₅ is demonstrated to possess a large amount of oxygen release/storage capacities depending on temperature even under flowing oxygen, as well as high oxygen storage/release properties and reversibility under alternating inert and oxygen gases at 500 °C. Substituting Ga on the Al-site would reduce the oxygen storage capacities, even though these substituted samples still posses good reversibility. The effect of A-site species (Mg, Ca, Sr) have been also investigated and demonstrated. It can't obtain pure brownmillerite-type crystal structure when Ca is partially or totally substituted by Mg or Sr, resulting in poor reversibility and low oxygen storage capacities. Nanostructured layered-perovskite La₁.₇Ca₀.₃M₁₋ₓCuₓO[sub](4-δ) (M = Fe, Co, Ni, Cu) have also been investigated for oxygen storage and as potential cathodes for IT-SOFCs. Even though the as-prepared layered-perovskite oxides have been demonstrated to be good candidates as cathode materials for IT-SOFCs with high performance, they do not possess high amount of oxygen storage/release ability under inert atmospheres because of the robust phase stability. β-MnO₂ nanorods can release large amount of oxygen (ca. 9.2 wt%) with increasing temperature at about 560 °C under various gases (air, N₂). Coating β-MnO₂ nanorods with CeO₂ nanocrystals could result in lower temperatures for oxygen mobility and removal under N₂ because of the enhanced oxygen mobility between CeO₂₋ₓ and β-MnO₂, while coating β-MnO₂ nanorods with SnO₂ nanocrystals have no enhanced oxygen mobility behaviours. The results demonstrate the positive and negative synergetic effect between other metal oxides and β-MnO₂ on the oxygen migration. Cr- and Cu-doped CeO₂ nanocrystals (i.e. nanorods, nanocubes and nanoparticles) were chosen to investigate the effect of transition-metal doping on CeO₂ and their valence changes with temperature and various atmospheres, as well as their oxygen storage capacities. The effect of Cr- or Cu- doping on CeO₂ nanocrystal morphology and oxygen storage capacities have been investigated and demonstrated. This provides some basic information for transition-metals doped CeO₂ nanocrystal evolution and stability, as well as further applications in energy-related fields, such as three-way catalysts, electrode materials in solid oxide fuel cells and Li-air batteries.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19727号 / 工博第4182号 / 新制||工||1645(附属図書館) / 32763 / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 田中 勝久, 教授 平尾 一之, 教授 三浦 清貴 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM