Date of Award

6-12-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Tansel Karabacak

Abstract

Photocatalysis using nanostructured semiconductors for the degradation of organic pollutants has received significant attention as an advanced water treatment method. A photocatalyst absorbs light with energy greater than or equal to its band gap and generates electron-hole pairs. These electrons and holes take part in redox reactions in water to generate reactive oxygen species, such as hydroxyl radicals and superoxide anions, which can break down organic contaminants. However, this method has some challenges, such as electron-hole recombination, which reduces the efficiency, high cost of nanostructure synthesis, and reduced durability of nanostructured photocatalysts in suspension form. The immobilization of photocatalyst nanostructures on supports is a potential solution for improving durability. Additionally, immobilization on metallic substrates could facilitate fast charge transfer and enhanced light scattering. However, this design has the disadvantage of reduced surface area. The goal of this dissertation was to synthesize ZnO nanostructures of different designs by a low-cost, environmentally friendly, and scalable hot water treatment method, and to directly compare the photocatalytic activities of the different designs. Furthermore, this study introduced a novel hot water deposition method to deposit CuOx on ZnO nanostructures aiming to form a heterojunction, which can reduce electron-hole recombination and improve durability. ZnO nanostructures in suspension form and fixed on Zn surfaces were synthesized, and materials characterization by SEM, EDS, TEM, XRD, XPS, UV-Vis, and Raman spectroscopy was done to analyze the nanostructure morphology, composition, crystal structure, and optical properties. The photocatalytic properties of the ZnO nanostructures were studied via methylene blue degradation tests under UV light and calculating the degradation percentage and rate constant.

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