Date of Award
Spring 5-9-2026
Document Type
Honors Thesis
Department/Major
Chemistry
First Advisor
James D. Hoefelmeyer
Second Advisor
Zhenqiang Wang
Third Advisor
Chaoyang Jiang
Keywords
Photocatalysis, TiO₂ Nanocrystals, Co Dopants, Heterojunctions, NiO-TiO₂ Nanocrystals, Ball Milling
Subject Categories
Inorganic Chemistry
Abstract
Carbon emissions and fossil fuel usage has increased dramatically in recent decades, and the need for renewable energy has grown with it. Photocatalytic processes on titanium dioxide (TiO₂) nanocrystals may be used for solar energy driven production of fuel/oxidizer pairs. Many different methods have been developed to increase the effectiveness of TiO₂ in photocatalysis, including dye sensitization, quantum dot sensitization, doping with metals and non-metals, and the surface attachment of cocatalyst materials. Impurity dopants are not susceptible to photo-bleaching or degradation and judicious selection of cocatalyst materials can lead to robust all-inorganic heteronanocrystal photocatalysts: whereas, the use of molecular dye and quantum dot sensitization, while well-established as increasing photocatalytic performance in TiO₂ based materials, suffer from rapid photodegradation. Long term energy solutions will likely require inexpensive, stable materials with high photocatalytic activity. Given these performance requirements, we tested the capabilities and effectiveness of two materials: cobalt-doped TiO₂ and NiO-TiO₂ heteronanocrystals. In comparison to TiO₂ the light absorbance of the Co-doped TiO₂ was increased into the visible region. We also found that NiO-TiO₂ catalyzes light-driven water oxidation to hydrogen peroxide and showed higher activity than TiO₂ due to the separation of photogenerated charges within the material. These results show the importance and potential of nanoscale material design to improve photocatalytic performance in materials that could lead to new pathways for the solar energy utilization and help reduce the need for fossil fuels.
Recommended Citation
Haack, Lara A., "Increasing Photocatalytic Activity of TiO₂ Nanocrystals with Cobalt Dopants and NiO Heterojunctions" (2026). Honors Thesis. 421.
https://red.library.usd.edu/honors-thesis/421