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Structure, texture and surface acidity studies of a series of mixed zinc–aluminum (60–90 molar % Al) phosphate catalysts
Author(s) -
Mtalsi Karim,
Jei Taib,
Montes Mario,
Tayane Souad
Publication year - 2001
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.354
Subject(s) - calcination , thermogravimetric analysis , zinc , fourier transform infrared spectroscopy , chemistry , inorganic chemistry , catalysis , differential thermal analysis , coprecipitation , desorption , adsorption , thermal desorption spectroscopy , infrared spectroscopy , crystallization , nuclear chemistry , chemical engineering , organic chemistry , physics , optics , diffraction , engineering
A series of mixed zinc–aluminum phosphate (ZnAlP) catalysts containing 40–90 aluminum molar % were synthesized by a coprecipitation method and characterized by nitrogen adsorption–desorption, X‐ray diffraction, FTIR spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature programmed desorption (TPD) of ammonia. The presence of aluminum greatly affected the surface properties of Zn 3 (PO 4 ) 2 by delaying the crystallization process of Zn 3 (PO 4 ) 2 . All amorphous samples were shown to be mesoporous and they contained two types of aluminum surface hydroxyl groups and one type of phosphorus hydroxyl group, as shown by DRIFT spectra. The specific surface area and the acidity of ZnAlP increased on increasing the aluminum content. On the other hand, a great difference in the texture and the concentration of surface acid sites was found by changing the precipitating agent and calcination temperature. Thus these factors also play an important role in the final properties of these catalysts. © 2001 Society of Chemical Industry