Document Type
Thesis
Date of Award
2025
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
James Hoefelmeyer
Abstract
High dependence on fossil fuels for energy carries risks for the environment, health, energy, and geopolitical stability. One of the solutions to address this is solar energy utilization, and the use of semiconductors for photocatalytic water splitting is a tantalizing prospect. An n-type semiconductor TiO2 combined with p-type NiO producing a heteronanojunction shows effective light-driven oxidation of H2O into H2O2. We developed a synthetic method to attach NiO nanoparticles on the surface of anatase TiO2 nanorods. We characterized the materials with UV-visible spectroscopy, powder X-ray diffraction, and electron microscopy. We immobilized the HNCs on fumed silica and removed organic surfactants with vacuum oven treatment. We demonstrated light-driven oxidation of water to H2O2 on SiO2/NiO-TiO2 that leads to a steady-state concentration of hydrogen peroxide in aqueous solution. In the presence of an electron scavenger, AgNO3, the initial rate of formation of hydrogen peroxide and its steady-state concentration increased with the increase of AgNO3 concentration. Together, the results suggest a closed photocatalytic cycle in which hydroxide ion is oxidized to hydroxyl radical, which is in equilibrium with hydrogen peroxide, and the reduction of hydroxyl radical to hydroxide ion. In the presence of a fast electron scavenger, the reduction of hydroxyl radical must compete, which allows the system to reach a greater steady-state concentration of hydrogen peroxide.
Subject Categories
Chemistry
Keywords
Heterojunction Hydrogen Peroxide Light-driven Nickel Oxide Titanium Dioxide Water Oxidation
Number of Pages
68
Publisher
University of South Dakota
Recommended Citation
Swadhen, Mahfuz Ahammed, "HYDROGEN PEROXIDE PRODUCTION FROM LIGHT-DRIVEN WATER OXIDATION VIA NICKEL OXIDE-TITANIUM DIOXIDE HETERONANOCRYSTALS" (2025). Dissertations and Theses. 356.
https://red.library.usd.edu/diss-thesis/356