Nanoscale TiO2 and Fe2O3 architectures for solar energy conversion schemes

Bibliography: p. 86-94Many pages in colour.Copy of copyright permissions included. Original copyright permissions with original Partial Copyright Licence.The direct conversion of sunlight into more useable forms of energy has the potential of alleviating the environmental and social problems associated with a dependence on fossil fuels. If solar energy is to be utilized en-masse, however, it must be inexpensive and widely available. In this vein, the focus of this thesis is on nanostructured materials relevant to solar energy conversion and storage. Specifically, this thesis describes the ambient sol-gel synthesis of titanium dioxide (TiO2) nanowires designed for enhanced charge-transfer in solar collection devices, and the synthesis of novel disordered metal-oxide (MOx) catalysts for water oxidation. The introductory chapter of this thesis gives an overview of the vanous approaches to solar energy conversion. Sol-gel reaction conditions that enable the growth of one-dimensional (1-D) anatase TiO2 nanostructures from fluorine-doped tin oxide (FTO) for photovoltaics (PVs) are described in the second chapter. The generation of these linear nanostructures in the absence of an external bias or template is achieved by using facile experimental conditions (e.g., acetic acid (HO Ac) and titanium isopropoxide (Ti(OiPr)4) in anhydrous heptane). The procedure was developed by functionalizing basetreated substrates with Ti-oxide nucleation sites that serve as a foundation for the growth of linear Ti-oxide macromolecules, which upon calcination, render uniform films of randomly oriented anatase Ti02 nanowires. A systematic evaluation of how reaction conditions (e.g., solvent volume, stoichiometry of reagents, substrate base treatment) affect the generation of these Ti02 films is presented. A photo-organic MOx deposition route (i.e., photochemical metal-organic deposition (PMOD)) used to deposit thin-films of amorphous iron oxide (a-Fe2O3) for water oxidation catalysis is detailed in third chapter. It is shown that the irradiation of a spin-coated metal-organic film produces a film of non-crystalline a-Fe2O3. It is shown that annealing at various temperatures produces a-Fe2O3 films with variable electronic properties and catalytic activities in the context of water oxidation. The study revealed that a-Fe2O3 are superior water oxidation catalysts (WOCs) relative to crystalline forms produced by high temperature annealing of the thin-films. This research has important implications in the conversion of sunlight into electricity, and then into hydrogen fuels

DESIGN RING THROTTLE CONFUSED FOR HYDRO-PNEUMATIC

The peculiarities of the ring design confused throttle. The dependences for calculating the minimum area cross-section and a working area of the current coordinate. The estimation of the in-fluence of the main geometrical parameters of the throttle on the hydraulic losses

Karta Siebenundzwanzig User s Manual

The basic use of a concept map is to illustrate and gain insight about the relationships between certain ideas or concepts . Concept maps are very useful visual aids; they are often helpful for understanding complex relationships very quickly. A basic concept map usually consists of some combination of nodes and arcs. A node represents a certain concept and an arc represents a relationship between two or more nodes. Arcs are also used to show relationships between relationships (arcs can be connected to arcs). Using nodes and arcs, very complex relationships can be demonstrated visually.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

The Karta-CASA Framework: Concept Mapping and Multi-Agent Systems

This paper describes the Karta-Casa project, an attempt to design an agent framework that provides a flexible, extensible and easy-to-use base for constructing various single-user and distributed groupware visualization and concept mapping applications. The structure and the development process behind Karta-CASA are detailed, and several novel aspects of the system are described. Details of several applications based on the framework are provided. Further, this paper suggests several research directions for extending the Karta-CASA system into areas that have not yet been explored by other agent visualization systems.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

Photochemical Route for Accessing Amorphous Metal Oxide Materials for Water Oxidation Catalysis

International audienceLarge-scale electrolysis of water for hydrogen generation requires better catalysts to lower the kinetic barriers associated with the oxygen evolution reaction (OER). Although most OER catalysts are based on crystalline mixed-metal oxides, high activities can also be achieved with amorphous phases. Methods for producing amorphous materials, however, are not typically amenable to mixed-metal compositions. We demonstrate that a low-temperature process, photochemical metal-organic deposition, can produce amorphous (mixed) metal oxide films for OER catalysis. The films contain a homogeneous distribution of metals with compositions that can be accurately controlled. The catalytic properties of amorphous iron oxide prepared with this technique are superior to those of hematite, whereas the catalytic properties of a -Fe 100- y - z Co y Ni z O x are comparable to those of noble metal oxide catalysts currently used in commercial electrolyzers