자료유형 | 학위논문 |
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서명/저자사항 | (Ga1-xZnx)(N1-xOx) Nanocrystals: Photochemical H2 Production and Spatial Characterization of Electronic Structure. |
개인저자 | Hall, Leah Margaret Graham. |
단체저자명 | University of Colorado at Boulder. Chemistry. |
발행사항 | [S.l.]: University of Colorado at Boulder., 2019. |
발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
형태사항 | 131 p. |
기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
ISBN | 9781088322659 |
학위논문주기 | Thesis (Ph.D.)--University of Colorado at Boulder, 2019. |
일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Advisor: Dukovic, Gordana. |
이용제한사항 | This item must not be sold to any third party vendors. |
요약 | Solar fuel generation via artificial photosynthesis is a promising pathway to a clean and sustainable source of energy. Nanoscale (Ga1-xZnx)(N1-xOx) has been synthesized in the solid state in order to answer the call for new multinary semiconductors for use in solar fuel generation. Herein, the solid-state mechanism of (Ga1-xZnx)(N1-xOx) nanocrystal formation involving phase transformation of cubic spinel ZnGa2O4 to wurtzite (Ga1-xZnx)(N1-xOx) and diffusion of the elements combined with nitrogen incorporation will be discussed. Understanding how multinary semiconductor compounds function and drive multi-electron photochemical reactions is of the utmost importance for potentially using them in solar applications. One goal is to utilize (Ga1-xZnx)(N1-xOx) nanocrystals for solar photochemistry and understand why their efficiencies have been historically low. The use of (Ga1-xZnx)(N1-xOx) nanocrystals for photochemical H2 generation in an aqueous system with a redox mediator will be discussed. The four-part H2 generation system uses (Ga1-xZnx)(N1-xOx) nanocrystals as a light absorber, methyl viologen as an electron relay, Pt nanoparticles as a cocatalyst, and dithioerythritol as a sacrificial hole scavenger. Each charge-transfer step is studied in isolation in order to evaluate the factors that determine the overall photochemical efficiency. It is concluded that electron transfer from(Ga1-xZnx)(N1-xOx) to MV2+ is likely the most limiting step for the overall system. To date, little analysis has been done on the electronic structure of (Ga1-xZnx)(N1-xOx), particularly for samples with different elemental distributions. How the electronic structure changes when comparing homogeneous and heterogeneous (Ga1-xZnx)(N1-xOx) nanocrystals and how the electronic structure changes spatially throughout a single particle will be investigated. It is found that the heterogeneous (Ga1-xZnx)(N1-xOx) nanocrystals show two energy transitions, one in the UV region and one in the visible region, while the homogeneous particles only show a visible transition. Additionally, the shape of the energy loss spectrum stays constant throughout a particle indicating that the electronic structure is constant in a single particle. |
일반주제명 | Chemistry. Nanoscience. Materials science. Biochemistry. |
언어 | 영어 |
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