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| Type |
Symposium |
| Area |
Recent Physical Chemistry Studies on Energy and Catalysis |
| Room No. |
304호 |
| Time |
FRI 15:10-: |
| Code |
PHYS3-3 |
| Subject |
Electronic structures of photo-catalytic activities of TiO2 nanoparticles |
| Authors |
이진용
성균관대학교 화학과, Korea |
| Abstract |
We investigate the influence of size and structure on the electronic structure of 0.5-3.2 nm diameter TiO2 nanoparticles in both vacuum and water using density functional theory calculations. Specifically, we track the optical and electronic band gap of a set of (TiO2)n nanoparticles ranging from small non-bulk-like clusters with n=4, 8 and 16, to larger nanoparticles with n=35 and 84 derived from cuts from the anatase bulk crystal structure. As the difference between these two energy gaps (the exciton shift) tends to zero in the bulk we use the magnitude of this shift as an indicator of how bulk-like the electronic structure of our nanoparticles are and how it is affected by size and structure. Extrapolating our results to larger sizes we thus provide a rough estimate of the nanoparticle size at which the electronic structure will begin to be effectively bulk-like. Our results generally confirm that the electronic structure of the nanoparticles has a significantly more pronounced structure dependency than size dependency. We also show that the exciton state is thermodynamically favored over free charged species both in vacuum and in water. We also investigate the effect of oxygen vacancies in TiO2 nanoparticles, (TiO2)35, on the photo-catalytic activities. We tested all the possible single oxygen vacancies and compared the energy levels, and found the enhanced photo-catalytic activity by single oxygen vacancy is due to the apperance of intermediate states. |
| E-mail |
jinylee@skku.edu |
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119th General Meeting of the KCS