One-step sol-gel synthesis of sulfated-zirconia catalysts

Sulfated-zirconia catalysts were prepared by a one-step sol-gel method. Two different protocols were studied in which sulfuric acid is introduced either with the hydrolysis water, or in the zirconium alkoxide solution in n-propanol. After calcination at 923 K these two materials were compared with sulfated-zirconia prepared in two steps by post-sulfation of zirconium hydroxide obtained either by the sol-gel method or by precipitation of inorganic salts. The sulfated-zirconias prepared by the one-step protocol are the most active catalysts for the hydroconversion of n-hexane. Moreover, the sample prepared by adding sulfuric acid through the hydrolysis water exhibits different textural properties and enhanced activity for n-hexane conversion. These different behaviours cannot be explained by the sulfur content.