Surface properties of mesoporous catalytic supports

The influence of the processing parameters on the properties of zirconia, a lumina and silica MCM-41 has been investigated. Digestion of the precursors leads to zirconia, alumina and silica MCM-41 with higher surface area and better thermal stability. The effects of digestion are attributed to increa sed dehydroxylation, strengthening of the network between primary particles , and to a decrease in the number of surface defects. In the case of zircon ia and alumina, digestion also increased the surface acidity. This may be d ue to the smaller crystallites which expose low-coordinated sites at the su rface. Al-MCM-41 prepared by post-synthesis grafting of aluminum is compare d with MCM-41 prepared by direct incorporation of aluminum during synthesis . The surface Si/Al ratio was determined using XPS and correlated to the ca talytic activity of the Al-MCM-41 for the synthesis of jasminaldehyde. (C) 2001 Elsevier Science B.V. All rights reserved.