波谱学杂志 ›› 2005, Vol. 22 ›› Issue (1): 61-66.

• 研究论文 • 上一篇    下一篇

脱铝丝光沸石中扭曲四配位铝的27Al 3Q MAS NMR研究

  

  1. 南开大学 1.化学学院, 2.物理学院,天津  300071
  • 收稿日期:2004-09-13 修回日期:2004-10-25 出版日期:2005-03-05 发布日期:2005-03-05
  • 基金资助:

    国家自然科学基金(29803004,20233030,20373029), 教育部高等学校骨干教师基金(GG-703-10055-1008)资助项目.

Detection of Distorted Tetrahedral-Coordinate Aluminum in Dealuminated Mordenite by 27Al 3Q MAS NMR

  1. 1.Department of Chemistry, 2.Department of Physics, Nankai University, Tianjin, 300071, China
  • Received:2004-09-13 Revised:2004-10-25 Online:2005-03-05 Published:2005-03-05
  • Supported by:

    国家自然科学基金(29803004,20233030,20373029), 教育部高等学校骨干教师基金(GG-703-10055-1008)资助项目.

摘要:

27Al MAS, 3Q MAS NMR研究了脱铝的丝光沸石和无定形硅铝胶中的铝配位态,在丝光沸石中检测到归属于扭曲四配位铝(Distorted Tetrahedrally Coordinated Al,  DTA)的信号,通过与无定形硅铝胶的比较,发现扭曲四配位铝的存在是活化和脱铝酸性沸石的典型特征. 从这些结果推断:DTA可能是沸石骨架脱铝形成非骨架铝的中间状态.

关键词: 核磁共振, 多量子魔角旋转核磁共振, 脱铝, 丝光沸石, 扭曲四配位铝

Abstract:

27Al MAS and 3Q MAS NMR spectroscopy was applied to study the aluminum coordination in dealuminated zeolite mordenite and amorphous silica alumina. A signal ascribed to distorted tetrahedral coordinate Al (DTA) was detected. By comparison with amorphous silica alumina, it was found that the presence of distorted tetrahedral coordinate species is a typical feature in crystalline zeolites after activation and dealumination. From these experimental results we suggest that the DTA species, which are absent in amorphous silicaalumina, locate at the interface between the crystalline framework lattice and the extra-framework species formed by dealumination.

Key words: NMR, multiple quantum magic angle spinning (3Q MAS) NMR, mordenite, dealumination, distorted tetrahedral-coordinated Al (DTA)

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