Impact of supercritical drying with excess solvent on textural properties of Ti-HMS catalyst support

Abstract

Textural characteristics of catalysts and catalysts supports are of a prime importance when it comes to their application in processing of high molecular weight compounds. Drying procedure is a key factor in preservation of wet gel properties. Hexagonal mesoporous silicas (HMS) doped with Ti-ions is finding a promising usage as heterogeneous catalysts support. In this paper, the effect of supercritical drying with excess solvent on the textural characteristics of Ti-HMS is addressed. HMS with Ti ions (Si/Ti atomic ratio of 40) is prepared using the sol-gel method. Dodecylamine is used as the structure directing surfactant (S) and TEOS and Titanium butoxide as the inorganic precursors (I). Specific surface area, mesoporosity and pore volume of the support dried by thermal evaporation of solvent in air and dried in excess of supercritical ethanol are compared. The results indicate that improved specific surface area and almost four times bigger value for mesopore volume are obtained using supercritical drying procedure.