الفهرس 
Chapter 1 : Introduction and Objectives of InvestigationOnly 14 pages are availabe for public view
 |  | from | 215 |  |  |
| | | from | 215 | | |
Abstract
The present thesis work was focused on serious research attempts to prepare, characterize and evaluate perovskite-type oxides of atomic-level mixed metal ions (Fe, Mn, Bi, La, Co and Sr) as decomposition catalysts for H2O2 in solution and 2-propanol (2-PrOH) in the gas phase. It is, thus, a chemical mixing of different metal ions in the framework of perovskite-type (cubic (c), orthorhombic (o) or rhombohedral (r)) oxide lattices. Accordingly, a sol-gel processing was carried out to prepare 80 oC-dried gels of metal alkoxide or carboxylate complex compounds using 2-mothoxyethanol (ME) and/or ethylene glycol (EG), and citric acid (CT) as ligands (i.e. chelating agents) . The resulting parent materials were found by means of (IR), (UV-Vis DRS), (TG) and (DTA) were employed to determine the calcination temperature (viz., 700 oC) at which the various binary (ABO, where A = Bi or La, and B = Fe or Mn) or ternary ((SrxA1-x)BO or A(CoxB1-x)O) metal oxides are thermally genesized from the parent materials. Subsequently, X-ray powder diffractometry (XRD), IR, UV-Vis DRS, and N2 sorptiometry were applied in order to determine bulk and surface properties of the calcination products; namely, crystalline phase composition and crystallite average sizes, chemical composition, electronic properties, and specific surface area. Then, the catalytic decomposition activity of the calcination products towards H2O2 in solution was followed by means of gravimetric gasometry, whereas that towards 2-PrOH in the gas phase by means of in-situ IR spectroscopy. Results obtained were correlated with the determined properties for the test catalysts.
The thesis manuscript is made up of five chapters. Chapter 1 sets out literature back ground information about structural and formability parameters of perovskite-type mixed oxides, as well as their methods of synthesis and prominent applications in the field of heterogeneous catalysis. Chapter 2 details materials used and the sol-gel processing applied to prepare the mixed oxides parent materials, as well as the apparatus and methods used to characterize and evaluate the catalytic decomposition activity of the study materials. Chapter 3 presents and discusses bulk and surface characterization results obtained for ferrite-based binary and ternary metal oxides. Chapter 4 presents and discusses bulk and surface characterization results obtained for manganite-based binary and ternary metal oxides. Results and discussion of the catalytic decomposition activity of test mixed oxide catalysts are set out in Chapter 5, as well as activity-property correlations thereby established.
The present thesis work was focused on serious research attempts to prepare, characterize and evaluate perovskite-type oxides of atomic-level mixed metal ions (Fe, Mn, Bi, La, Co and Sr) as decomposition catalysts for H2O2 in solution and 2-propanol (2-PrOH) in the gas phase. It is, thus, a chemical mixing of different metal ions in the framework of perovskite-type (cubic (c), orthorhombic (o) or rhombohedral (r)) oxide lattices. Accordingly, a sol-gel processing was carried out to prepare 80 oC-dried gels of metal alkoxide or carboxylate complex compounds using 2-mothoxyethanol (ME) and/or ethylene glycol (EG), and citric acid (CT) as ligands (i.e. chelating agents) . The resulting parent materials were found by means of (IR), (UV-Vis DRS), (TG) and (DTA) were employed to determine the calcination temperature (viz., 700 oC) at which the various binary (ABO, where A = Bi or La, and B = Fe or Mn) or ternary ((SrxA1-x)BO or A(CoxB1-x)O) metal oxides are thermally genesized from the parent materials. Subsequently, X-ray powder diffractometry (XRD), IR, UV-Vis DRS, and N2 sorptiometry were applied in order to determine bulk and surface properties of the calcination products; namely, crystalline phase composition and crystallite average sizes, chemical composition, electronic properties, and specific surface area. Then, the catalytic decomposition activity of the calcination products towards H2O2 in solution was followed by means of gravimetric gasometry, whereas that towards 2-PrOH in the gas phase by means of in-situ IR spectroscopy. Results obtained were correlated with the determined properties for the test catalysts.
The thesis manuscript is made up of five chapters. Chapter 1 sets out literature back ground information about structural and formability parameters of perovskite-type mixed oxides, as well as their methods of synthesis and prominent applications in the field of heterogeneous catalysis. Chapter 2 details materials used and the sol-gel processing applied to prepare the mixed oxides parent materials, as well as the apparatus and methods used to characterize and evaluate the catalytic decomposition activity of the study materials. Chapter 3 presents and discusses bulk and surface characterization results obtained for ferrite-based binary and ternary metal oxides. Chapter 4 presents and discusses bulk and surface characterization results obtained for manganite-based binary and ternary metal oxides. Results and discussion of the catalytic decomposition activity of test mixed oxide catalysts are set out in Chapter 5, as well as activity-property correlations thereby established.