Metal organic frameworks have gained much attention due to their tunable pore sizes and very high surface areas. With the discovery many of these type materials the need has raised to look into new applications of theses porous frameworks. This thesis focuses on the synthesis of a new perovskite-type metal organic framework and measurement of its thermal conductivity in search of its applicability as a thermoelectric material. The second part of this work focuses on the synthesis of a metal organic framework incorporated with a Lewis pair for the first time. The optimum loading amount of the Lewis pair into the framework was also investigated.

Compounds in the series La1-xTiO3 have been prepared in the powder and single crystalline forms. The structures of these compounds were studied with x-ray, neutron, and electron diffraction techniques. In all cases, a distortion from the ideal perovskite structure was found. Throughout the series, transitions occur in structural, magnetic, and electrical properties. The structure of La.67TiO3 was found to be of a distorted perovskite type arising from distortions in the titanium octahedra as a result of an ordering of the lanthanum positions and A-site cation vacancies. Although this phase has been reported many times, the crystal structure has not been determined. The La.67TiO3 and La.70TiO3 phases have the same structure and were assigned to the Pmmn space group. At La75.TiO3, a Ti3+ concentration of 2 8%, the symmetry of the structure changes from Pmmn to Imma, and distortion of the perovskite structure is caused by octahedral tilting within the lattice. A further structural transition occurs at a Ti3+ concentration of 64%, La8gTiO3, where the symmetry changes from Imma to Pnma. Again distortions from the ideal perovskite structure are caused by octahedral tilts within the system. Transitions were also observed in electrical and magnetic properties. These transitions occur at the same Ti3+ concentrations as the transitions observed in the structural properties, which suggests a correlation between properties based on Ti3+ concentration. The occurrence of A-site cation vacancies within the lattice is directly related to the Ti3+ concentrations within the individual materials. Changes in the Ti3+ concentration affect the size of the unit cell as well as the electrical and magnetic properties which range from insulators at low Ti3+ concentrations to metals at high Ti3+ concentrations. / Thesis / Master of Science (MSc)

Šiame darbe vienfazis perovskito struktūros gadolinio aliuminatas GdAlO3 zolių-gelių metodu buvo gautas 1000 oC temperatūroje, gadolinio jonų šaltiniu naudojant Gd2O3, kompleksus sudarančiu reagentu – 1,2 etandiolį, natūralią vyno rūgštį, citrinų rūgštį arba citrinų rūgšties ir etanolamino mišinį. Sintetinant GdAlO3, gautų tyrimų rezultatai parodė, kaip yra svarbu zolių gelių procese pasirinkti tinkamas pradines medžiagas bei kompleksus su metalais sudarančius reagentus: gadolinio jonų šaltiniu naudojant Gd2O3 buvo gauti geresni rezultatai nei naudojant Gd(NO3)3•6H2O, vienfazis GdAlO3 gali būti sėkmingai susintetintas kompleksus sudarančiu reagentu naudojant tiek natūralią vyno rūgštį, tiek 1,2 etandiolį, tiek citrinų rūgštį, tiek citrinų rūgšties ir etanolamino mišinį. Nustatyta, kad sintetinant stronciu pakeistus gadolinio aliuminatus Gd1–xSrxAlO3– (x = 0,10, 0,25, 0,50, 0,75), tinkamesnis gadolinio jonų šaltinis yra gadolinio oksidas nei gadolinio nitratas heksahidratas, kompleksus sudarantis reagentas – EDTA nei natūrali vyno rūgštis. Vienfazis perovskito struktūros stronciu pakeistas gadolinio aliuminatas Gd0,90Sr0,10AlO3– buvo susintetintas zolių-gelių metodu 1000 oC temperatūroje, gadolinio jonų šaltiniu naudojant Gd2O3, stroncio jonų šaltiniu – Sr(NO3)2, kompleksus sudarančiu reagentu – EDTA. Be to, 800 ºC iškaitinimo temperatūra yra per maža šiems junginiams sintetinti. Pirmą kartą pasiūlytas vandeninis zolių gelių metodas lantano ir gadolinio kobaltatams... [toliau žr. visą tekstą] / In the present thesis the reported results let us to conclude that the developed aqueous sol–gel procedure could be successfully used for the low-temperature synthesis of monophasic perovskite gadolinium aluminate ceramics. It was also demonstrated that the selection of raw materials for the sol–gel processing should be done with care. Monophasic perovskite structure gadolinium aluminate GdAlO3 has been synthesized by sol gel synthesis method at 1000 oC, using gadolinium oxide as gadolinium raw material and 1.2 ethanediol, natural tartaric acid, citric acid or mixture of citric acid and ethanolamine as complexing agent. According to the XRD results, the Gd2O3 instead of Gd(NO3)36H2O preferably should be used as starting material for the preparation of GdAlO3. Monophasic perovskite structure strontium substituted gadolinium aluminate Gd0.90Sr0.10AlO3– was synthesized by the same sol gel synthesis method at 1000 oC, using gadolinium oxide as gadolinium raw material, strontium nitrate as strontium ion source and EDTA as complexing agent. It was proved that better gadolinium ion source is gadolinium oxide than gadolinium nitate hexahydrate, better complexing agent – EDTA than natural tartaric acid in the synthesis of GdAlO3 and strontium substituted Gd1–xSrxAlO3– (x = 0.10, 0.25, 0.50, 0.75) samples. According to the XRD results, increasing amount of strontium reduces amount of peaks of perovskite structure gadolinium aluminate. Besides, 800 ºC temperature is too low for the... [to full text]

In the present thesis the reported results let us to conclude that the developed aqueous sol–gel procedure could be successfully used for the low-temperature synthesis of monophasic perovskite gadolinium aluminate ceramics. It was also demonstrated that the selection of raw materials for the sol–gel processing should be done with care. Monophasic perovskite structure gadolinium aluminate GdAlO3 has been synthesized by sol gel synthesis method at 1000 oC, using gadolinium oxide as gadolinium raw material and 1.2 ethanediol, natural tartaric acid, citric acid or mixture of citric acid and ethanolamine as complexing agent. According to the XRD results, the Gd2O3 instead of Gd(NO3)36H2O preferably should be used as starting material for the preparation of GdAlO3. Monophasic perovskite structure strontium substituted gadolinium aluminate Gd0.90Sr0.10AlO3– was synthesized by the same sol gel synthesis method at 1000 oC, using gadolinium oxide as gadolinium raw material, strontium nitrate as strontium ion source and EDTA as complexing agent. It was proved that better gadolinium ion source is gadolinium oxide than gadolinium nitate hexahydrate, better complexing agent – EDTA than natural tartaric acid in the synthesis of GdAlO3 and strontium substituted Gd1–xSrxAlO3– (x = 0.10, 0.25, 0.50, 0.75) samples. According to the XRD results, increasing amount of strontium reduces amount of peaks of perovskite structure gadolinium aluminate. Besides, 800 ºC temperature is too low for the... [to full text] / Šiame darbe vienfazis perovskito struktūros gadolinio aliuminatas GdAlO3 zolių-gelių metodu buvo gautas 1000 oC temperatūroje, gadolinio jonų šaltiniu naudojant Gd2O3, kompleksus sudarančiu reagentu – 1,2 etandiolį, natūralią vyno rūgštį, citrinų rūgštį arba citrinų rūgšties ir etanolamino mišinį. Sintetinant GdAlO3, gautų tyrimų rezultatai parodė, kaip yra svarbu zolių gelių procese pasirinkti tinkamas pradines medžiagas bei kompleksus su metalais sudarančius reagentus: gadolinio jonų šaltiniu naudojant Gd2O3 buvo gauti geresni rezultatai nei naudojant Gd(NO3)3•6H2O, vienfazis GdAlO3 gali būti sėkmingai susintetintas kompleksus sudarančiu reagentu naudojant tiek natūralią vyno rūgštį, tiek 1,2 etandiolį, tiek citrinų rūgštį, tiek citrinų rūgšties ir etanolamino mišinį. Nustatyta, kad sintetinant stronciu pakeistus gadolinio aliuminatus Gd1–xSrxAlO3– (x = 0,10, 0,25, 0,50, 0,75), tinkamesnis gadolinio jonų šaltinis yra gadolinio oksidas nei gadolinio nitratas heksahidratas, kompleksus sudarantis reagentas – EDTA nei natūrali vyno rūgštis. Vienfazis perovskito struktūros stronciu pakeistas gadolinio aliuminatas Gd0,90Sr0,10AlO3– buvo susintetintas zolių-gelių metodu 1000 oC temperatūroje, gadolinio jonų šaltiniu naudojant Gd2O3, stroncio jonų šaltiniu – Sr(NO3)2, kompleksus sudarančiu reagentu – EDTA. Be to, 800 ºC iškaitinimo temperatūra yra per maža šiems junginiams sintetinti. Pirmą kartą pasiūlytas vandeninis zolių gelių metodas lantano ir gadolinio kobaltatams... [toliau žr. visą tekstą]

Ce travail est né de l'idée d'associer l'ingénierie des matériaux sous forme de couches minces, domaine qui motive depuis de nombreuses années les chercheurs du LMGP, à des substrats piézoélectriques à fort coefficients de déformation. Les matériaux piézoélectriques peuvent convertir une énergie électrique en une énergie mécanique (de déformation) et vice-versa. Il est alors aisé d'imaginer qu'une couche mince synthétisée à la surface d'un substrat piézoélectrique profitera de la déformation de ce dernier quand il est soumit à un champ électrique. Le substrat mis en jeu est le PMN-PT, composé qui présente de forts coefficients de déformation. Dans cette étude le film synthétisé et mis en œuvre est le LaNiO3. Il cristallise dans une structure pérovskite ABO3. Cette structure présente l'avantage de permettre une grande variété de distorsions structurales et peut accueillir un grand nombre d'éléments chimiques. / This work was born from the idea of ​​combining materials in thin films form, an area that motivates many years researchers LMGP, to substrates with high piezoelectric coefficients of deformation. Piezoelectric materials can convert electrical energy into mechanical energy (strain) and vice versa. So we can imagine that a thin film synthesized on the surface of a piezoelectric substrate will benefit from the substrate deformation when subjected to an electric field. The substrate involved is the PMN-PT, a compound that shows high piezoelectric coefficient. In this study the film synthesized is the LaNiO3. It crystallizes in a perovskite structure ABO3. This structure has the advantage of a wide variety of structural distortions and can accommodate a large number of chemical elements.

No description available.

My main objective is to gain a firm understanding of the correlation between the defect chemistry and the properties of Ba-based perovskite structure proton-conducting ceramics, especially B-site doped BaCeO3, so as to allow the engineering of these compounds with the desired properties for the application in devices; develop membranes of mixed protonic-electronic conductors suitable for hydrogen separation from gas mixtures; and further advance hydrogen separation technology by gaining fundamental understanding about electrochemical separation mechanism. BZCY proton conductors with various compositions have been synthesized and characterized. The absence of low-angle supercell reflections indicates a random B-site cation distribution. The substitution of Zr led to a decrease in cell volume and an enhanced structural stability against reactions with CO2. The total conductivity for BZCY pellets increased with temperature increased and decreased as the zirconium content increased at each fixed temperature. Dense Ni-BZCY composite membranes have been successfully fabricated for evaluating hydrogen permeability and stability. Doping Zirconium in the B-site only slightly reduced the hydrogen permeation at high temperatures, but dramatically increased the chemical stability in CO2- and H2O-containing gases. Among the compositions studied, the Ni-BZCY7 exhibited both highest H2 permeation rate and good chemistry stability, thus having potential for practical applications.

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21122号 / 工博第4486号 / 新制||工||1697(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 田中 庸裕, 教授 陰山 洋, 教授 佐藤 啓文 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The functional oxides are performing materials showing interestant properties. The study of the local environment respect to the average struvture is essential for the deep understanding of the correlations between structure and properties ; this investigation of short and medium range can be performed with the use of solid state NMR techniques. In particular in this thesis three different classes of materials for applications in fields of optic and energy are considered : perovskite structure LaSrAlO4, the melilite system LaSr(Ga/Al)3O7 and the family of orthosylicates Li2(Fe/Mn)SiO4.