Mesoporous MCM-41 aluminosilicates as model silica-alumina catalysts: Spectroscopic characterization of the acidity

Conference · Mon Dec 30 23:00:00 EST 1996

OSTI ID:468019

Di Renzo, F; Chiche, B; Fajula, F ^[1]; Viale, S; Garrone, E ^[2]

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1. ENSCM, Montpellier (France)
2. Universita di Torino (Italy)

The synthesis procedure brings about a low threshold value for the surface concentration of Al species and renders MCM-41 a model system for the study of silica-alumina phases. On severely outgassed samples, two types of Lewis sites are present, differing in their protrusion from the surface, as well as Bronsted sites engaged in lateral H-bonding, evidenced by the interaction with NH{sub 3} and CO. The conversion of Lewis sites into Bronsted ones by water adsorption shows that the Bronsted species are Si(OH)Al, typical of zeolites, and Si-Al(OH)-Si, found in dealuminated zeolites. The flexibility of the amorphous framework accounts for the differences with zeolitic aluminosilicates.

• OSTI ID: 468019
• Report Number(s): CONF-960652--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM 27
ALUMINIUM OXIDES
BOND LENGTHS
BROENSTED ACIDS
CATALYSTS
INORGANIC ACIDS
LEWIS ACIDS
MOLECULAR STRUCTURE
NMR SPECTRA
SILICA
SURFACE PROPERTIES
X-RAY DIFFRACTION