A new low-cost synthetic route to obtain zirconium containing mesoporous silica

Abstract

A new alternative low-cost route to obtain zirconium doped mesoporous silica has been developed by using cheaper inorganic Zr and Si precursors different from alkoxides and a non-ionic surfactant template, polyethyleneoxide. A series of solids, with Si/Zr molar ratios ranging from 5 to infty, was prepared. The resulting materials are stable at high temperatures, exhibit high BET-surface areas, thick pore walls and high tunable acidity. These characteristics make them excellent candidates to be used in heterogeneous catalysis as both acid catalysts and catalytic supports, as well as adsorbents. The incorporation of zirconium into the silica framework provokes a linear increase of both the Lewis and Brønsted acidities as probed by adsorption of basic molecules, such as pivalonitrile and pyridine, coupled to IR spectroscopy. This acid character has also been corroborated by the catalytic test of 2-propanol conversion, where the dehydration product, propene, is the only product formed at 200 °C.