Hierarchical assembly of immobilized TiO2-based nanostructured epitaxial films on Ti Substrates for photocatalytic water decontamination and hydrogen generation

This PhD thesis primarily involved the hierarchical assembly of immobilized TiO2-based epitaxial crystalline thin film photocatalysts that are anchored and grown directly from crystalline Ti substrates. The synthesized novel photocatalysts featuring various nanostructures presented herein include nanotubes, nanowhiskers, nanowires, nanofungus and nanocubes. The different morphologies have imparted various functionalities and also tailor surface- and shaped-induced properties of semiconductor nanocrystalline phase. The increased surface area and reactive sites also resulted in a consistently higher activity for surface-based processes such as heterogeneous photocatalysis. The developed photocatalysts were employed to degrade recalcitrant, emerging contaminants and pathogens that are commonly present in water bodies (AO7, E. coli cells and BPA) via production of photogenerated holes and oxidative radicals. The free electrons produced from photocatalytic reduction half-reactions are harvested and utilized for the reduction of hydroxide ions present in the treated water to generate hydrogen gas, a source of clean energy.DOCTOR OF PHILOSOPHY (ENV.SC. and ENG.