| 研究課題/領域番号 |
25390144
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| 研究機関 | 東北大学 |
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研究代表者 |
ZHANPEISOV N.U. 東北大学, 高度教養教育・学生支援機構, 准教授 (10326275)
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| 研究期間 (年度) |
2013-04-01 – 2016-03-31
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| キーワード | IRMOF structure / DFT / B3LYP/6-31G* / Cluster calculations |
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| 研究実績の概要 |
Systematic high-level DFT calculations have been performed for screening the most reliable and desirable structures for IRMOF materials at the B3LYP/6-31G* level. The original clusters have been created based on berillium-based metal oxide connector parts and benzenedicarboxylate organic linkers mimicking IRMOF structure (starting from the small C48H30Be4O25 to larger C160H96Be16O84 cluster models), and then have been modified by replacement of the connector parts with the more basic metal oxides or more amphoteric ones. These modifications include the replacement of OBe4O12(C6) connector units by OMg4O12(C6), or OZn4O12(C6), or OAl2Li2O12(C6) as well as with a complex OMgTi3O15(C6) and led us to increase the basicity of oxide connector fragments that makes one effectively tune active sites for hydrogen or other gas interactions with their outer surfaces with relatively small energy barriers. As a result, the increased basicity of oxide anion sites and the unit-cell size of overall modified IRMOF materials have been achieved that makes it as efficient and potential material for hydrogen storage.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
In overall, the project is going rather smoothly even the size of clusters used in our cluster calculations are not so small. New workstation HPC5000-Z820-SIP with the installed Gaussian09 program packages and other our computer facilities were found very efficient to handle these our DFT theoretical studies. From these studies we have found that the modification of metal oxide connector part with the OAl2Li2O12(C6) ones lead us to a substantial polarization of whole the structure where one can distinguish electron-rich LiO4 and electron-poor AlO4 tetrahedral units. The best IRMOF material can be obtained by a replacement of the precursor connector with a complex OMgTi3O15(C6) ones that resembles a cube structure metal oxide core where the cube corners are alternately occupied by Ti4+ and O2- (except just one Ti4+ which is replaced by Mg2+) while there would not be an unwanted extra oxide anion that occupied the bulk position of the cube. As a result more basic three-fold coordinated oxide centers will be formed and exposed to the incoming hydrogen molecules.
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| 今後の研究の推進方策 |
In the final year of the project, we plan to carry out systematic extended calculations mimicking the activation of hydrogen molecule(s) on these modified IRMOF materials as well as on modified Carbon K4 by applying ONIOM-like methodology to full-extent characterization of these structures. The ONIOM calculations will be based on two or three layer approximations where the high-level must include electron-correlation effects to describe properly weak interactions of adsorbate molecules with the active sites of interest. These considerations will be then extended to clarify adsorption modes of different molecules (CO2, CH4, water, etc.). One of the most important issues here is to find the applicability of these materials (like other carbon-based materials - fullerenes, SWNT, nanostructures, etc.) in gas storage and gas separation as well as waste-water clean-up efforts.
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| 次年度使用額が生じた理由 |
To dissiminate the results of the present study, we would like to attend the incoming International Conferences and Congress of Quantum Chemistry. Also we should summarize the obtained results as a regular paper in an International refereed journals.
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| 次年度使用額の使用計画 |
We plan to attend the 15th International Congress of Quantum Chemistry (15thICQC) in Beijing (China), the 8th Conference of Asian Consortium on Computational Materials Science in Taipei (Taiwan) and the 6th JCS Computational Chemistry Symposium in Smolenice (Slovakia).
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