ISSN:
1572-879X
Keywords:
Brønsted acidity of zeolites
;
N2 and CO probes
;
H-bonding
;
FTIR spectroscopy
;
adsorption-induced change of vibrational frequencies and intensities
;
density functional cluster models
;
gradient corrected exchange-correlation functionals
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The interaction of N2 with Brønsted acid centers of H-ZSM-5 zeolite has been investigated employing Fourier transform infrared spectroscopy and cluster model calculations based on a gradient corrected density functional method. A comparison is made with CO, which is widely used as a probe for surface acidity. It is shown that the computational approach is capable of almost quantitatively reproducing a number of sensitive parameters of the H-bonded dinitrogen and carbonyl complexes, like adsorption energy, adsorption-induced changes of the vibrational frequencies and of their intensities. According to a constraint space orbital variation analysis, the carbonyl and dinitrogen complexes mainly differ by the somewhat stronger σ donation ability of CO as compared to N2. It is concluded that dinitrogen may serve as a convenient probe for the acidity of zeolites.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00808840
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