A high-resolution solid-state NMR study on nano-structured HZSM-5 zeolite

	A high-resolution solid-state NMR study on nano-structured HZSM-5 zeolite
	Zhang, WP ; Bao, XH ; Guo, XW ; Wang, XS
刊名	catalysis letters
	1999
卷号	60 期号:1-2 页码:89-94
关键词	solid-state NMR nano-structured HZSM-5 zeolite probe molecule perfluorotributyl amine ((n-C4F9)(3)N)
英文摘要	variations in the structure and acidity properties of hzsm-5 zeolites with reduction in crystal sizes down to nanoscale (less than 100 nm) have been investigated by xrd, tem and solid-state nmr with a system capable of in situ sample pretreatment. as evidenced by a combination of al-27 mas nmr, si-29 mas, cp/mas nmr and h-1 mas nmr techniques, the downsize of the zeolite crystal leads to an obvious line broadening of the al-27, si-29 mas nmr spectrum, an increasing of the silanol concentration on the external surface, and a pronounced alteration of the acidity distribution between the external and internal surfaces of the zeolite. in a hzsm-5 zeolite with an average size at about 70 nm, the nonacidic hydroxyl groups (silanols) are about 14% with respect to the total amount of si, while only 4% of such hydroxyl groups exist in the same kind of zeolite at 1000 nm crystal size. the result of h-1 mas nmr obtained using fluorinert(r) fc-43 (perfluorotributyl amine) as a probe molecule demonstrates that most of the silanols are located on the external surface of the zeolite. moreover, the concentration of bronsted acid sites on the external surface of the nano-structured zeolite appears to be distinctly higher than that of the microsized zeolite.
WOS标题词	science & technology ; physical sciences
类目[WOS]	chemistry, physical
研究领域[WOS]	chemistry
关键词[WOS]	acid sites ; catalytic cracking ; crystallite size ; zsm-5 zeolites ; particle-size ; bronsted-acid ; cavern design ; selectivity ; resonance ; molecules
收录类别	SCI
原文出处	true
语种	英语
WOS记录号	WOS:000081052800014
公开日期	2010-11-30
内容类型	期刊论文
源URL	[http://159.226.238.44/handle/321008/85651]
专题	大连化学物理研究所_中国科学院大连化学物理研究所
作者单位	1.Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Catalysis, Dalian 116023, Peoples R China 2.Dalian Univ Technol, Lab Comprehens Utiliz Carbonaceous Resources, Dalian 116012, Peoples R China
推荐引用方式 GB/T 7714	Zhang, WP,Bao, XH,Guo, XW,et al. A high-resolution solid-state NMR study on nano-structured HZSM-5 zeolite[J]. catalysis letters,1999,60(1-2):89-94.
APA	Zhang, WP,Bao, XH,Guo, XW,&Wang, XS.(1999).A high-resolution solid-state NMR study on nano-structured HZSM-5 zeolite.catalysis letters,60(1-2),89-94.
MLA	Zhang, WP,et al."A high-resolution solid-state NMR study on nano-structured HZSM-5 zeolite".catalysis letters 60.1-2(1999):89-94.