Synthesis of mesoporous SiO 2–ZrO 2 mixed oxides by sol–gel method

Abstract

A series of SiO 2–ZrO 2 mixed oxides were prepared by sol–gel method in the presence of directing agent, with variable amounts of ZrO 2 between pure silica and pure zirconia, with the aim to obtain catalytic materials suitable as solid acid catalysts. SiO 2–ZrO 2 mixed oxides differ from the two pure starting oxides. While SiO 2 has a low OH density without peculiar acid character, the introduction of increasing amounts of Zr increases the density of the acid sites in the materials. Furthermore both SiO 2/ZrO 2 molar ratio and drying procedure are able to influence the physico-chemical characteristics (textural properties, acid sites distribution, etc.) of these mixed oxides.