Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Bronsted acid sites

	Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Bronsted acid sites
	Liu, HM; Shen, WJ; Bao, XH; Xu, YD
刊名	applied catalysis a-general
	2005-10-13
卷号	295 期号:1 页码:79-88
关键词	methane dehydroaromatization Mo/HZSM-5 H-1 MAS NMR Bronsted acid sites
通讯作者	徐奕德
产权排序	1;1
英文摘要	the catalytic performances of methane dehydroaromatization (mda) under non-oxidative conditions over 6 wt.% mo/hzsm-5 catalysts calcined for different durations of time at 773 k have been investigated in combination with ex situ h-1 mas nmr characterization. prolongation of the calcination time at 773 k is in favor of the diffusion of the mo species on the external surface and the migration of mo species into the channels, resulting in a further decrease in the number of bronsted acid sites, while causing only a slight change in the mo contents of the bulk and in the framework structure of the hzsm-5 zeolite. the moq(x) species associated and non-associated with the bronsted acid sites can be estimated quantitatively based on the 1h mas nmr measurements as well as on the assumption of a stoichiometry ratio of 1: 1 between the mo species and the bronsted acid sites. calcining the 6 wt.% mo/hzsm-5 catalyst at 773 k for 18 h can cause the moox species to associate with the bronsted acid sites, while a 6 wt-% mo/sio2 sample can be taken as a catalyst in which all moox species are non-associated with the bronsted acid sites. the tof data at different times on stream on the 6 wt.% mo/hzsm-5 catalyst calcined at 773 k for 18 h and on the 6 wt-% mo/sio2 catalyst reveal that the mocx species formed from moox associated with the bronsted acid sites are more active and stable than those formed from moox non-associated with the bronsted acid sites. an analysis of the tpo profiles recorded on the used 6 wt.% mo/hzsm-5 catalysts calcined for different durations of time combined with the tga measurements also reveals that the more of the mocx species formed from moox species associated with the br6nsted acid sites, the lower the amount of coke that will be deposited on it. the decrease of the coke amount is mainly due to a decrease in the coke burnt-off at high temperature. (c) 2005 elsevier b.v. all rights reserved.
WOS标题词	science & technology ; physical sciences ; life sciences & biomedicine
类目[WOS]	chemistry, physical ; environmental sciences
研究领域[WOS]	chemistry ; environmental sciences & ecology
关键词[WOS]	solid-state nmr ; dehydro-aromatization ; mas nmr ; nonoxidative conditions ; zeolite catalysts ; bifunctional catalysis ; carbonaceous deposits ; dilute ethylene ; hzsm-5 zeolite ; conversion
收录类别	SCI
原文出处	true
语种	英语
WOS记录号	WOS:000233062500009
公开日期	2010-11-30
内容类型	期刊论文
源URL	[http://159.226.238.44/handle/321008/93101]
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	Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Catalysis, Dalian 116023, Peoples R China
推荐引用方式 GB/T 7714	Liu, HM,Shen, WJ,Bao, XH,et al. Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Bronsted acid sites[J]. applied catalysis a-general,2005,295(1):79-88.
APA	Liu, HM,Shen, WJ,Bao, XH,&Xu, YD.(2005).Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Bronsted acid sites.applied catalysis a-general,295(1),79-88.
MLA	Liu, HM,et al."Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Bronsted acid sites".applied catalysis a-general 295.1(2005):79-88.