Acidity and catalytic activities of sulfated zirconia inside SBA-15

SBA-15 containing various amount (10–50 wt.%) of highly dispersed ZrO2 is prepared using urea hydrolysis method. The sulfated zirconia (ZrO2) in SBA-15 catalysts were prepared using these materials. The materials were characterized by XRD, BET surface area, TEM, TGA, acidity measurements using in situ IR pyridine adsorption, sulfate content and catalytic activities were studied for cumene cracking and esterification of cyclohexanol. The Brönsted acidity, catalytic activity for cumene cracking and esterification and sulfate content were found to pass through a maxima where ZrO2 loading is 35 wt.%. The 35SZ-SBA catalysts exhibited 6.4 times higher activity for cumene cracking compared to the bulk SZ catalysts. The relationship between acidity, sulfate content and catalytic activity are discussed in the light of existing knowledge on sulfated zirconia.