Issue 41, 2015

Acidity of two-dimensional zeolites


Hybrid quantum mechanics:molecular mechanics (QM/MM) calculations of absolute deprotonation energies are performed with periodic boundary conditions for Brønsted sites of aluminosilicate bilayers with various Al/Si ratios (two-dimensional zeolite). The supercell method is applied and density functional theory is used. Much lower values are obtained (1042, 1069 and 1091 kJ mol−1 for Al/Si = 1/63, 1/7 and 1/3, respectively) than those for bulk zeolites (1233 kJ mol−1 for H-chabazite with Al/Si = 1/11). We ascribe the much lower deprotonation energy to the smaller effective dielectric constant (1.6–1.9) of an ultra-thin dielectric in a vacuum compared to that of the corresponding bulk systems (3.0 for H-chabazite), which leads to a better stabilization of the charge created upon deprotonation.

Graphical abstract: Acidity of two-dimensional zeolites

Supplementary files

Article information

Article type
26 Aug 2015
14 Sep 2015
First published
06 Oct 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2015,17, 27873-27882

Acidity of two-dimensional zeolites

M. Rybicki and J. Sauer, Phys. Chem. Chem. Phys., 2015, 17, 27873 DOI: 10.1039/C5CP05088J

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