含氮ZSM-5分子筛骨架中氮取代位置的密度泛函计算  

Density Functional Theory Studies on the Substitutional Site of Nitrogen in the Nitrogen-Incorporated ZSM-5 Zeolite

作　　者：武光军[1] 王鑫[1] 于爱敏[1] 王贵昌[1] 杨雅莉[1] 章福祥[1] 关乃佳[1] 

机构地区：[1]南开大学化学学院材料化学系新催化材料科学研究所,天津300071

出　　处：《高等学校化学学报》2008年第12期2403-2406,共4页Chemical Journal of Chinese Universities

基　　金：国家'九七三'计划(批准号:2009CB623502);国家自然科学基金(批准号:20573059;20777039)资助

摘　　要：运用Gaussian 98程序包,采用密度泛函理论B3LYP方法,基于ZSM-5分子筛的8T模型,分别通过6-31G,6-31G(d)和6-311G(d,p)基组计算了ZSM-5分子筛中氮原子取代前后各O原子和各N原子的能量,从而得到各O原子与各N原子在骨架中的稳定性及其对氮化取代反应的影响.计算结果表明,N原子在骨架中的稳定性对氮取代反应的影响较大.ZSM-5分子筛晶体结构中与B酸位处于同一个四面体的O11位置,为氮原子的最佳取代位置,因此氮化后分子筛表面的B酸强度得到较大程度的减弱.Density Functional Theory study was performed to predict the nitrogen substitutional site in the framework of nitrogen-incorporated ZSM-5 zeolite.All the calculations were performed on 8T clusters of ZSM-5 by Gaussian 98 program at B3LYP/6-31G,B3LYP/6-31G（d）and B3LYP/6-311G（d,p）levels,respectively.The calculations on energies of O atoms and N atoms show that the stability of N atoms in the framework has bigger effect on the reaction of substitution than the stability of O atoms.The O11 site,which is in the same tetrahedron with Brnsted acid,is the most preferred site for nitrogen substitution in the framework of ZSM-5 zeolite.So the Br nsted acidity on the surface of zeolite after nitridation is decreased.

关 键 词：ZSM-5分子筛 密度泛函理论 氮化 取代 

分 类 号：O641[理学—物理化学]