Self-ordering titania nanotube arrays: electrochemical anodization, functionalization, and application

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Title Self-ordering titania nanotube arrays: electrochemical anodization, functionalization, and application
Publication Type dissertation
School or College College of Mines & Earth Sciences
Department Metallurgical Engineering
Author Smith, York Reed
Date 2014-08
Description Hydrogen is envisioned as a viable fu e l o f the future. Photoelectrochemical (PEC) hydrogen generation by water splitting reaction is the most promising method to obtain renewable hydrogen. The U.S. Department of Energy has determined that for PEC hydrogen to be economically feasible, and competitive with steam reforming hydrogen production, a solar-to-hydrogen efficiency of 10% maintained for 1 ,0 0 0 hours of operation is required. Selection of durable photo-electrodes capable of withstanding the harsh aqueous environment in PEC hydrogen generation is an important factor. Semiconductor nanostructured metal oxides, such as titanium dioxide, are generally more stable in such environments, making them suitable candidate materials. In the present investigation, self-organizing nanotubular titanium dioxide synthesized by electrochemical anodization and heterostructures thereof were examined for PEC hydrogen generation. In the first part, new synthesis methods were explored such as light-assisted anodization, surface treatment prior to anodization to achieve hierarchical nanotubular titanium dioxide, and binary acid anodization for in situ metal doping. A mechanism for pore nucleation and nanotube wall separation has also been proposed. In the second part, titania nanotubes were sensitized with nanocrystalline CdO, CdS, and Mn2+ or Co2+ doped CdS as visible light absorber layers. The material properties were examined using different characterization techniques such as scanning electron microscopy (SEM), x-ray diffraction (XRD), ultra violet-visible (UV-vis) photospectroscopy, x-ray photon spectroscopy (XPS), and Raman spectroscopy. The PEC activity of the photoanodes was examined under simulated air mass (AM) 1.5 irradiation. Electrochemical impedance spectroscopy and Mott-Schotty analysis were also used to ascertain the PEC results and correlate with material properties.
Type Text
Publisher University of Utah
Dissertation Institution University of Utah
Dissertation Name Doctor of Philosophy
Language eng
Rights Management Copyright © York Reed Smith 2014
Format application/pdf
Format Medium application/pdf
Format Extent 2,134,802 bytes
Identifier etd3/id/3177
ARK ark:/87278/s6fz0jnb
Setname ir_etd
ID 196743
Reference URL https://collections.lib.utah.edu/ark:/87278/s6fz0jnb
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