Periodic density functional investigation of Lewis acid sites in zeolites:: relative strength order as revealed from NH3 adsorption

被引：22

作者：

Elanany, M

Koyama, M

Kubo, M

Broclawik, E

Miyamoto, A

机构：

[1] Tohoku Univ, Grad Sch Engn, Dept Appl Chem, Aoba Ku, Sendai, Miyagi 9808579, Japan

[2] Japan Sci & Technol Agcy, PRESTO, Kawaguchi, Saitama 3320012, Japan

[3] Tohoku Univ, New Ind Creat Hatchery Ctr, Aoba Ku, Sendai, Miyagi 9808579, Japan

来源：

APPLIED SURFACE SCIENCE | 2005年 / 246卷 / 1-3期

关键词：

mordenite; Lewis acid site; acidity; ammonia adsorption; DFr; dealumination;

D O I：

10.1016/j.apsusc.2004.10.052

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Different types of cationic species acting as Lewis acid sites as well as Na-counter ion in dealuminated zeolites are investigated, for the first time, using periodic density functional method. The energy of ammonia adsorption is taken as a measure for the acidity. The results reveal that the relative strength of the investigated active sites increases in the order: Na+ < Al(OH)(2)(+) < AlO+ < equivalent to Si+. Moreover, the interaction of NH3 with tri-coordinated aluminum dislodged in the framework is less favorable than that with the neighboring silicon ion. (c) 2004 Elsevier B.V. All rights reserved.

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收藏

页码：96 / 101

页数：6

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