Using trimethylphosphine as a probe molecule to study the acid states in Al-MCM-41 materials by solid-state NMR spectroscopy
文献类型：期刊论文
| 作者 | Luo, Q ; Deng, F ; Yuan, ZY ; Yang, J ; Zhang, MJ ; Yue, Y ; Ye, CH |
| 刊名 | JOURNAL OF PHYSICAL CHEMISTRY B
 |
| 出版日期 | 2003 |
| 卷号 | 107期号:11页码:2435 |
| 关键词 | DOUBLE-RESONANCE NMR SURFACE HYDROXYL-GROUPS H-1/AL-27 TRAPDOR NMR ZEOLITE HY SIEVE MCM-41 COUPLING-CONSTANT BRONSTED ACIDITY AB-INITIO AL-27 MAS H-1 MAS |
| ISSN号 | 1520-6106 |
| 通讯作者 | Deng, F (reprint author), Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China. |
| 中文摘要 | Using trimethylphosphine (TMP) as a probe molecule, acid sites in a series of Al-MCM-41 materials with Si/Al ratios ranging from 16 to 80 were investigated by various solid-state NMR techniques including Si-29, P-31, Al-27, H-1 magic-angle spinning (MAS), and some double- or triple-resonance methods such as P-31 --> H-1 cross polarization (CP), H-1/Al-27, and H-1/P-31/Al-27 TRAPDOR (transfer of population in double resonance). By means of the H-1/Al-27 TRAPDOR technique, which has the ability to establish a correlation between 1H and Al-27, the hydroxyl groups associated with Al could be discriminated from the silanol groups. Two signals at 3.5 and 1.9 ppm were observed in the H-1/Al-27 TRAPDOR spectra; they are likely due to the bridging hydroxyl (SiOHAl) and aluminum hydroxyl groups, respectively. P-31 MAS NMR strongly supports the formation of zeolitelike Bronsted acid sites in the mesoporous material after the incorporation of aluminum. The concentration of the Bronsted sites determined from P-31 MAS NMR is about 2 orders of magnitude lower than that of total SiOH groups, which renders their direct observation by H-1 MAS NMR spectroscopy difficult. However, these sites can be well studied by P-31 --> H-1 CP/MAS and various triple-resonance TRAPDOR NMR techniques, which provide a more detailed description of the interactions between TMP and the different hydroxyl groups in the Al-MCM-41 materials. Although the acid strength of the Bronsted sites in the Al-MCM-41 materials is lower than that of microporous zeolites such as HY, these sites can protonate TMP molecules. Some of the framework T-site aluminum atoms are not associated with the bridging hydroxyl groups and are probably present as Al-OH. No Lewis acid sites were found in our samples, though the Al-27 MAS spectra show the existence of five-coordinate extra framework aluminum. |
| 收录类别 | SCI |
| 语种 | 英语 |
| 公开日期 | 2013-09-23 |
| 源URL | [http://ir.iphy.ac.cn/handle/311004/46470]  |
| 专题 | 物理研究所_物理所公开发表论文_物理所公开发表论文_期刊论文 |
| 推荐引用方式 GB/T 7714 | Luo, Q,Deng, F,Yuan, ZY,et al. Using trimethylphosphine as a probe molecule to study the acid states in Al-MCM-41 materials by solid-state NMR spectroscopy[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2003,107(11):2435. |
| APA | Luo, Q.,Deng, F.,Yuan, ZY.,Yang, J.,Zhang, MJ.,...&Ye, CH.(2003).Using trimethylphosphine as a probe molecule to study the acid states in Al-MCM-41 materials by solid-state NMR spectroscopy.JOURNAL OF PHYSICAL CHEMISTRY B,107(11),2435. |
| MLA | Luo, Q,et al."Using trimethylphosphine as a probe molecule to study the acid states in Al-MCM-41 materials by solid-state NMR spectroscopy".JOURNAL OF PHYSICAL CHEMISTRY B 107.11(2003):2435. |
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来源：物理研究所
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