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Synthesis and characterization of mesoporous silica-supported nano-crystalline sulfated zirconia catalysts prepared by a sol–gel process: Effect of the S/Zr molar ratio

Paper ID Volume ID Publish Year Pages File Format Full-Text
43501 45973 2007 9 PDF Available
Title
Synthesis and characterization of mesoporous silica-supported nano-crystalline sulfated zirconia catalysts prepared by a sol–gel process: Effect of the S/Zr molar ratio
Abstract

Mesoporous silica-supported nano-crystalline sulfated zirconia catalysts were prepared via the sol–gel process using an in situ sulfation. The parameter studied in this work was the S/Zr molar ratio. The synthesized solids were characterized using XRD, N2 physisorption, TG-DTA/SM, sulfur chemical analysis and adsorption–desorption of pyridine, and tested in the gas-phase acid-catalysed isomerization of n-hexane. The gelation process is highly affected by the sulfate loadings. Two gelation mechanisms were evidenced depending on the S/Zr molar ratio. The first one observed when 0.15 ≤ S/Zr ≤ 0.5, is characterized by a relatively high gelation rate. This mechanism favours the formation of two types of mesopores and a low percentage of retained sulfur. The second gelation mechanism occurs for higher S/Zr ratios: 0.5 ≤ S/Zr ≤ 1.2. In that case, slower gelation rates are observed. This slower gelation process leads to materials with reduced BET surface area but the amount of retained sulfur is increased. Appreciable catalytic properties were observed for the sample prepared with the highest S/Zr ratio, which presents the smallest size of sulfated zirconia crystallites and shows both Brönsted and Lewis acid sites on its surface.

Graphical abstractMesoporous silica-supported nano-crystalline sulfated zirconia catalysts were prepared via the sol–gel process using in situ sulfation. The parameter studied was the S/Zr molar ratio. Two gelation mechanisms were evidenced depending on this ratio. Appreciable catalytic properties in the n-hexane isomerization reaction were observed when the sample presents small size of sulfated zirconia crystallites and both Brönsted and Lewis acidities. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Sulfated zirconia; Nano-crystalline; Silica; n-Hexane; Acidity
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Synthesis and characterization of mesoporous silica-supported nano-crystalline sulfated zirconia catalysts prepared by a sol–gel process: Effect of the S/Zr molar ratio
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 328, Issue 1, 31 August 2007, Pages 43–51
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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Full-text PDF Download
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