Physico-chemical features and catalytic activity of sulfated zirconia prepared by sol-gel method. The role of the solvent evaporation step

Citation
S. Melada et al., Physico-chemical features and catalytic activity of sulfated zirconia prepared by sol-gel method. The role of the solvent evaporation step, CATAL LETT, 75(3-4), 2001, pp. 199-204
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics","Chemical Engineering
Journal title
CATALYSIS LETTERS
ISSN journal
1011-372X → ACNP
Volume
75
Issue
3-4
Year of publication
2001
Pages
199 - 204
Database
ISI
SICI code
1011-372X(2001)75:3-4<199:PFACAO>2.0.ZU;2-V
Abstract
ZrO2-SO4 powders have been prepared by following a single-step sol-gel prep arative route using zirconium propoxide as the starting compound. Sulfuric acid was employed both as the sulfating agent and as the catalyst of the po lycondensation reaction in the gel formation. Two different series of dried precursors were obtained by either evaporating the solvent in an oven at 1 00 degreesC (xerogels) or in supercritical conditions (aerogels). All the s amples were calcined at three temperatures (470, 550, and 630 degreesC) for the same time length (5 h). The powders were characterized for phase compo sition-crystallinity, surface area-porosity, sulfur content and surface sta te (XPS). The catalytic activity of the calcined samples was tested in the isomerization of n-butane in a continuous system at 150 degreesC in absence of H-2 and 250 degreesC in presence of H-2. The role played by the conditi ons of the solvent elimination, at the end of the sol-gel reaction, in affe cting the physicochemical and catalytic properties of the powders is discus sed.