Investigation of the distribution of acidity strength in zeolites by temperature-programmed desorption of probe molecules. 2. Dealuminated Y-type zeolites

Journal Article · Thu Jan 10 04:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100154a053· OSTI ID:5925997

Karge, H G; Dondur, V ^[1]; Weitkamp, J ^[2]

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1. Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (West Germany)
2. Univ. of Stuttgart (West Germany)

The acidity of dealuminated hydrogen forms of Y-type zeolites (Si/Al = 2.4-8.6) is determined by temperature-programmed desorption of ammonia or pyridine, which is monitored through a mass spectrometer. Four types of acidic sites are indicated by ammonia, viz., weak Broensted and/or Lewis centers and medium and strong Broensted and strong Lewis sites. In contrast, pyridine, after sample activation at 675 K, probed only two types of sites, i.e., medium and strong Broensted sites. This difference is ascribed to different accessibility of sites for the two probe molecules. From the desorption spectra (i) the fractional coverage of the various sites, (ii) the most frequent energies of activation, {anti E}{sub d}, for desorption, and (iii) the probability functions of the activation energies are derived by using a previously described method of evaluation.

• OSTI ID: 5925997
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:1; ISSN JPCHA; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMMONIA
DATA
DESORPTION
EXPERIMENTAL DATA
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MASS SPECTROSCOPY
MATERIALS
MEASURING METHODS
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NUMERICAL DATA
PH VALUE
SPECTRA
SPECTROSCOPY
ZEOLITES