Functionalized TiO2 for Antifouling Photothermal Applications

  • Safa Alzaim

Student thesis: Master's Thesis

Abstract

Scalable photocatalytic and antifouling applications for thin films can be attained by extending the light absorption ability of titanium dioxide (TiO2) from the ultra violet to the visible range through hydrogenation. In the process of hydrogenating TiO2 thin films, the effect of the dopant on the electronic band structure is studied. Fabrication conditions of time, pressure, and temperature are optimized and catalysts for diatomic hydrogen dissociation are examined. Morphologies from chemical etching and electron beam evaporation fabrication are compared in terms of the photocatalytic response to hydrogenation. The diffusion path and diffusion mechanism of the dopant also underpins hydrogenation for photocatalysis. The effect of crystal size and morphology on charge carriers is also described; films annealed at different temperatures result in different morphologies, which influences the response to hydrogenation. Employing these principles, antifouling properties of hydrogenated and unhydrogenated TiO2 thin films and TiO2 nanostructures grown on a titanium substrate and CuO covered copper substrate are demonstrated through methylene blue degradation. The implications from the photocatalytic studies are applied to a solar steam generation device. This device uses a TiO2 based spectrally selective solar absorber to achieve thermal concentration; the absorber is mounted between a transparent cover and floating insulation foam to reduce heat losses. The wick is inserted through the floating foam to pump the water to the topmost surface with capillary forces for steam generation. By coating the CuO foam with TiO2 nanoparticles, the wick self-cleans organic contaminants, restoring performance during the liquid propagation. The wettability of the wick is studied in terms of the contact angle as well as roughness. The morphology of the TiO2/CuO is discussed in view of this spectral selectivity; CuO pillars and blades interact with clusters of TiO2 nanoparticles. This work thus examines the fundamentals of TiO2 microstructure for solar applications.
Date of AwardDec 2017
Original languageAmerican English

Keywords

  • Solar energy
  • Light Absorption
  • Hydrogenation
  • Thin Films
  • Anti-Fouling
  • Solar Applications
  • TiO2 Microstructures
  • Solar Power.

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