| Autor: |
L. Szirtes, J. Megyeri, K. Matusek, Giulio Alberti, Fabio Marmottini, S. Cavalaglio |
| Rok vydání: |
2001 |
| Předmět: |
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| Zdroj: |
Applied Catalysis A: General. 218:219-228 |
| ISSN: |
0926-860X |
| DOI: |
10.1016/s0926-860x(01)00648-2 |
| Popis: |
A composite of γ-zirconium phosphate (γ-ZrP) and silica (40% in weight of γ-ZrP) was prepared by hydrolysis of tetraethylsilicate in the presence of exfoliated γ-ZrP. The exfoliation of γ-ZrP was obtained in 1:1 (v/v) acetone/water solution at 80°C. The presence of silica prevented the re-aggregation of the exfoliated γ-ZrP lamellae. After heating at 650°C, the greater part of γ-ZrP was present in the composite as bilamellar packets of zirconium phosphate acid pyrophosphate while about 20% was transformed into α-Zr(O 3 POH) 2 . The surface acid POH groups of these lamellar species (about 1.1 meq. g −1 ) were not destroyed by thermal treatment up to 750°C. The composite exhibited a specific surface area of 421 m 2 g −1 of which about 191 m 2 g −1 was attributable to exfoliated lamellae of zirconium phosphate. The catalytic properties of the composite were preliminarily investigated for the conversion of ethylbenzene to styrene at different temperatures and different EB/O(air) ratios as a function of the contact time. The results are compared with pure γ-ZrP calcined at 650°C. Catalytic activity was strongly influenced by the total amount of the surface acidic groups of the samples. The γ-ZrP/SiO 2 composite showed a higher conversion rate (about five times) than calcined γ-ZrP. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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