中国科学院大连化学物理研究所机构知识库
Advanced  
DICP OpenIR  > 中国科学院大连化学物理研究所  > 期刊论文
题名: Mo/HMCM-22 catalysts for methane dehydroaromatization: A multinuclear MAS NMR study
作者: Ma, D;  Shu, YY;  Han, XW;  Liu, XM;  Xu, YD;  Bao, XH
刊名: JOURNAL OF PHYSICAL CHEMISTRY B
发表日期: 2001-03-08
DOI: 10.1021/jp002011k
卷: 105, 期:9, 页:1786-1793
收录类别: SCI
文章类型: Article
WOS标题词: Science & Technology ;  Physical Sciences
类目[WOS]: Chemistry, Physical
研究领域[WOS]: Chemistry
英文摘要: Detailed NMR investigations on fresh and coked Mo/HMCM-22 catalysts for methane dehydro-aromatization were presented. Al-27 MAS and Si-29 MAS as well as corresponding CP/MAS NMR experiments have proved that an interaction between molybdenum and the zeolite lattice occurs during the impregnation and calcination processes of the catalysts. With Bronsted acid sites serving as a powerful trap, molybdenum migrates into the internal channels of the zeolite and reacts preferentially with bridging hydroxyls groups. Thus, molybdenum is anchored to the framework aluminum through an oxygen bridge, which, in turn, modifies the acidic properties of the HMCM-22 and leads to a high dispersion of the molybdenum. If this kind of interaction becomes stronger, expelling of aluminum from the zeolite lattice would occur, with the forming of both octahedral nonframework aluminum and Al-2(MoO4)(3) crystallites, The latter can be hydrated to [Al(OH)(n)(H2O)(6-n)](n)(MoO4) (n = 1 or 2) in a water-saturated desiccator and can give a line at ca. 14 ppm in the Al-27 MAS NMR spectrum. UV-Raman results suggest that the carbonaceous deposits on the catalysts are mainly hydrogen-deficient aromatic type, which are also verified by H-1 --> Si-29 CP/MAS and H-1 --> Al-27 CP/MAS NMR, as well as the failure for conducting the C-13 CP/MAS NMR experiment. H-1 --> Al-27 CP/MAS NMR experiments indicate that most of the coke is deposited on framework aluminum (Bronsted site). Regeneration in an oxygen atmosphere leads to the formation of a considerable amount of Al-2(MoO4)(3) crystallites. However, the catalytic activity can be properly restored after the regeneration; thus, the idea of taking this species as the detrimental factor for this reaction can be ruled out. On the other hand, lattice destruction of the zeolite is suggested to be responsible for the poor performance exhibited by the 10Mo/HMCM-22 catalyst. The synergic effect between molybdenum and Bronsted acid sites is considered to be the main reason for the outstanding catalytic performance of the 6Mo/HMCM-22 catalyst.
关键词[WOS]: NUCLEAR-MAGNETIC-RESONANCE ;  SUPPORTED MOLYBDENUM OXIDES ;  BRONSTED ACID SITES ;  MO-BASED CATALYSTS ;  STATE AL-27 NMR ;  ZEOLITE MCM-22 ;  MO/HZSM-5 CATALYSTS ;  HZSM-5 ZEOLITE ;  H-1 MAS ;  DEHYDRO-AROMATIZATION
语种: 英语
WOS记录号: WOS:000167267900018
Citation statistics: 
内容类型: 期刊论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/138849
Appears in Collections:中国科学院大连化学物理研究所_期刊论文

Files in This Item:

There are no files associated with this item.


作者单位: 1.Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Catalysis, Dalian 116023, Peoples R China

Recommended Citation:
Ma, D,Shu, YY,Han, XW,et al. Mo/HMCM-22 catalysts for methane dehydroaromatization: A multinuclear MAS NMR study[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2001,105(9):1786-1793.
Service
 Recommend this item
 Sava as my favorate item
 Show this item's statistics
 Export Endnote File
Google Scholar
 Similar articles in Google Scholar
 [Ma, D]'s Articles
 [Shu, YY]'s Articles
 [Han, XW]'s Articles
CSDL cross search
 Similar articles in CSDL Cross Search
 [Ma, D]‘s Articles
 [Shu, YY]‘s Articles
 [Han, XW]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
  Add to CiteULike  Add to Connotea  Add to Del.icio.us  Add to Digg  Add to Reddit 
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Powered by CSpace