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Effects of calcination temperature and water-washing treatment on n-hexane hydroisomerization behavior of Pt-promoted sulfated zirconia based catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
54813 47027 2013 7 PDF Available
Title
Effects of calcination temperature and water-washing treatment on n-hexane hydroisomerization behavior of Pt-promoted sulfated zirconia based catalysts
Abstract

Synthesis of Pt-promoted sulfated zirconia catalyst Pt/SO42−/ZrO2 (designated as PSZ), Pt/SO42−/ZrO2-Al2O3 (designated as PSZA), and Pt/SO42−/ZrO2-Al2O3-Y2O3 (designated as PSZAY) was reported. These catalysts were characterized by N2 adsorption–desorption, thermal gravimetric (TG) analysis, NH3-temperature programmed desorption (NH3-TPD), and H2-temperature programmed reduction (H2-TPR) techniques. Effects of calcination temperature of the catalysts on the n-hexane hydroisomerization behavior were investigated in details. The experiment results revealed that the addition of Al and Y or Al promoter alone could improve the thermal stability of the catalysts. PSZA and PSZAY exhibited higher isomerization activity than unmodified PSZ as the calcination temperature of sulfated Zr(OH)4 was relatively high, for example, between 650 °C and 750 °C. For the first time, it was found that water-washing treatment of PSZA and PSZAY at different preparation stages had considerably different impacts on their catalytic activity. Water-washing after calcination of the sulfated Zr(OH)4, the catalytic activity of PSZA and PSZAY was high, as indicated by approximately 80% of n-hexane conversion. However, water-washing before calcination of sulfated Zr(OH)4 led to a significant decrease in the catalytic activity of PSZA and PSZAY, that is, the n-hexane conversion diminished to around 35%. It was proposed that the presence of excessive sulfur species over sample was favorable for keeping the active sulfur species in the catalyst surface.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (201 K)Download as PowerPoint slideHighlights► Al and Y promoted Pt/SO42−/ZrO2 had higher isomerization activity than the unpromoted sample at high calcination temperature. ► The case is contrary at low calcination temperature. ► Water-washing before calcination of sulfated Zr(OH)4 led to a low catalytic activity. ► In contrast, water-washing after calcination had hardly effect on the catalytic activity.

Keywords
Hydroisomerization; Calcination temperature; Sulfated zirconia; Promoter; Water washing
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Effects of calcination temperature and water-washing treatment on n-hexane hydroisomerization behavior of Pt-promoted sulfated zirconia based catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 212, 1 September 2013, Pages 108–114
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
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us