高等学校化学学报

高等学校化学学报

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含氮ZSM-5分子筛骨架中氮取代位置的密度泛函计算

武光军, 王鑫, 于爱敏, 王贵昌, 杨雅莉, 章福祥, 关乃佳   

  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
  • 收稿日期:2008-10-26 修回日期:1900-01-01 出版日期:2008-12-10 发布日期:2008-12-10
  • 通讯作者: 关乃佳

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

WU Guang-Jun, WANG Xin, YU Ai-Min, WANG Gui-Chang, YANG Ya-Li, ZHANG Fu-Xiang, GUAN Nai-Jia*   

  1. Institute of New Catalytic Materials Science, Department of Materials Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
  • Received:2008-10-26 Revised:1900-01-01 Online:2008-12-10 Published:2008-12-10
  • Contact: GUAN Nai-Jia

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被引次数

1

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.

关键词: ZSM-5分子筛, 密度泛函理论, 氮化, 取代

Abstract: 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.

Key words: ZSM-5 zeolite, Density functional theory, Nitridation, Substitution

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