DFT study of the acid strength of MCM-22 with double Si/Al substitutions in 12MR supercage

	DFT study of the acid strength of MCM-22 with double Si/Al substitutions in 12MR supercage
	Zhou, DH ; He, N ; Wang, YQ ; Yang, G ; Liu, XC ; Bao, XH
刊名	journal of molecular structure-theochem
	2005-12-09
卷号	756 期号:1-3 页码:39-46
关键词	DFT study MCM-22 zeolite NNN-sites acidity of zeolites adsorption energy
英文摘要	dft calculations were performed on the acidity of mcm-22 zeolite with double si/al substitutions at nnn site in the 12 member-ring. two different cluster models were used to investigate the effect of different model structures on the calculated results. all calculations were carried out by using blyp functional and dnp basis set. the properties of si/al substitution energy, deprotonation energy, bridging hydroxyl stretching frequency and atomic charge on proton were calculated and used to measure bronsted acid strength. the nh3 adsorption on the acid site including adsorption energy and adsorbed configuration was found to be more rational character to investigate the intrinsic acidity of zeolite. through our calculations it was confirmed that the acidity in nnnn-substitution is stronger than nnn-substitution. for nnn-structure, hal4-hal4 has a slightly higher acidity than hal1-hal1. for nnnn-structure, if two protons are positioned outside of two al atoms, the acidity is the strongest; in other cases, if the second hydrogen is positioned between two al atoms, the acidity decreases. the calculated results are strongly dependent on the selected models. however, the adsorption energy of nh3 interacting with protonic zeolites shows minor dependency on the model structures. (c) 2005 elsevier b.v. all rights reserved.
WOS标题词	science & technology ; physical sciences
类目[WOS]	chemistry, physical
研究领域[WOS]	chemistry
关键词[WOS]	density-functional theory ; zeolite mcm-22 ; catalytic-properties ; external surface ; h-mcm-22 zeolite ; mas nmr ; sites ; framework ; aluminum ; behavior
收录类别	SCI
语种	英语
WOS记录号	WOS:000234161100006
公开日期	2015-11-10
内容类型	期刊论文
源URL	[http://159.226.238.44/handle/321008/139636]
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.Liaoning Normal Univ, Dept Chem & Chem Engn, Inst Chem Functionalized Mat, Dalian 116029, Peoples R China 2.Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Catalysis, Dalian 1160239, Peoples R China
推荐引用方式 GB/T 7714	Zhou, DH,He, N,Wang, YQ,et al. DFT study of the acid strength of MCM-22 with double Si/Al substitutions in 12MR supercage[J]. journal of molecular structure-theochem,2005,756(1-3):39-46.
APA	Zhou, DH,He, N,Wang, YQ,Yang, G,Liu, XC,&Bao, XH.(2005).DFT study of the acid strength of MCM-22 with double Si/Al substitutions in 12MR supercage.journal of molecular structure-theochem,756(1-3),39-46.
MLA	Zhou, DH,et al."DFT study of the acid strength of MCM-22 with double Si/Al substitutions in 12MR supercage".journal of molecular structure-theochem 756.1-3(2005):39-46.