Grafting sulfated zirconia on mesoporous silica

Abstract

Recently, sulfated zirconia has received considerable attention as a potential solid acid catalyst to replace problematic homogeneous acid catalysts. In this paper, the preparation and properties of acid catalysts obtained by grafting ziconia with atomic precision on MCM-41 mesoporous silica were studied. TEM and potential titration characterizations revealed that ZrO₂/MCM-41 with monolayer coverage can be obtained using this grafting technique. Sulfated ZrO₂/MCM-41 exhibits improved thermal stability than that of bulk sulfated zirconia, as evidenced by temperature programmed characterizations and XRD analysis. Temperature programmed reaction of isopropanol was used to evaluate the acidity of sulfated ZrO₂/MCM-41. It was found that the acid strength of sulfated ZrO₂/MCM-41 with monolayer coverage is weaker than bulk sulfated zirconia but stronger than SiO₂–Al₂O₃, a common strong acid catalyst.