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| 论文编号: |
122214O120110155 |
| 第一作者所在部门: |
603 、606组 |
| 中文论文题目: |
Location of Si Vacancies and [Ti(OSi)4] and [Ti(OSi)3OH] Sites in the MFI Framework: A Large Cluster and Full Ab Initio Study
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| 英文论文题目: |
Location of Si Vacancies and [Ti(OSi)4] and [Ti(OSi)3OH] Sites in the MFI Framework: A Large Cluster and Full Ab Initio Study
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| 论文题目英文: |
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| 作者: |
袁淑萍
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| 论文出处: |
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| 刊物名称: |
J. Phys. Chem. A
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| 年: |
2011
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| 卷: |
115 |
| 期: |
5 |
| 页: |
940 |
| 联系作者: |
袁淑萍 |
| 收录类别: |
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| 影响因子: |
2.732
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| 摘要: |
Titanium silicalite-1 (TS-1) is an important catalyst for selective oxidation reactions.However, the nature and structure of the active sites and the mechanistic details of the catalytic reactions over TS-1 have not been well-understood, leaving a continuous debate on the genesis of active sites on the TS-1 surface in the literature. In this work, the location of Si vacancies and [Ti(OSi)4] and [Ti(OSi)3OH] sites in the MFI (Framework Type Code of ZSM-5 (Zeolite Socony Mobile-Five)) framework has been studied using a full ab initio method with 40T clusters with a Si:Ti molar ratio of 39:1. It was shown that the former four energetically favorable sites for Si vacancies areT6, T12, T4, and T8 and for Ti centers of [Ti(OSi)4] are T10, T4, T8 and T11, being partially the same sites. Whether by replacing Si vacancies or substituting the fully coordinated Si sites, the most preferential site for Ti is T10, which indicates that the insertion mechanism does not affect the favorable sites of Ti in the MFI lattice. For the defective [Ti(OSi)3OH] sites, it was found that the Si vacancy at T6 with a Ti at its neighboring T9 site (T6-def-T9-Ti pair) is the most energetically favorable one, followed by a T6-def-T5-Ti pair with a small energy gap. These findings are significant to elucidate the nature of the active sites and the mechanism of reactions catalyzed by TS-1 and to design the TS-1 catalyst. |
| 英文摘要: |
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