Precursor type affecting surface properties and catalytic activity of sulfated zirconia

Zirconium-hydroxide precursor samples are synthesized from Zr-hydroxide, Zr-nitrate, and Zr-alkoxide, by precipitation/impregnation, as well as by a modified sol-gel method. Precursor samples are further sulphated for the intended SO4 2- content of 4 wt.%, and calcined at 500-700oC. Differences in precursors’ origin and calcination temperature induce the incorporation of SO4 2- groups into ZrO2 matrices by various mechanisms. As a result, different amounts of residual sulphates are coupled with other structural, as well as surface properties, resulting in various catalytic activities of sulphated zirconia samples. Catalyst activity and selectivity are a complex synergistic function of tetragonal phase fraction, sulphates contents, textural and surface characteristics. Superior activity of SZ of alkoxide origin can be explained by a beneficial effect of meso-pores owing to a better accommodation of coke deposits.

[1]  G. Bošković,et al.  Benefits of mesopores in sulfated zirconia catalyst , 2007 .

[2]  J. M. Serra,et al.  Discovery of new paraffin isomerization catalysts based on SO42−/ZrO2 and WOx/ZrO2 applying combinatorial techniques , 2003 .

[3]  T. Yamaguchi.  Alkane isomerization and acidity assessment on sulfated ZrO2 , 2001 .

[4]  R. Micic,et al.  n-Hexane isomerization over Pt-Na(H)Y catalysts obtained by different preparation methods , 2001 .

[5]  G. Yadav,et al.  Sulfated zirconia and its modified versions as promising catalysts for industrial processes , 1999 .

[6]  M. Muhler,et al.  Hydroisomerization of n-hexane over Pt/sulfated zirconia: activity, reversible deactivation, and surface analysis , 1999 .

[7]  B. Davis,et al.  Sulfated zirconia catalysts : characterization by TGA/DTA/mass spectrometry , 1995 .

[8]  K. P. Jong,et al.  The pivotal role of catalysis in energy related environmental technology , 1994 .

[9]  J. Parera.  Promotion of zirconia acidity by addition of sulfate ion , 1992 .

[10]  J. Sohn,et al.  Catalytic and surface properties of ZrO2 modified with sulfur compounds , 1989 .

[11]  G. Bošković,et al.  Content of sulfates and their stability: Key factors determining the catalytic activity of sulfated zirconia catalysts , 2007 .

[12]  H. Weyda,et al.  8 Modern refining concepts-an update on naphtha-isomerization to modern gasoline manufacture , 2003 .

[13]  P. Jacobs,et al.  Introduction to Acid Catalysis with Zeolites in Hydrocarbon Reactions , 1991 .