Ultrasonic preparation of mesoporous silica using pyridinium ionic liquid

TL;DR

This study explores ultrasonic synthesis of mesoporous silica using pyridinium ionic liquid as a co-solvent and pore template, revealing how ultrasound and ionic liquids influence pore structure and material properties.

Contribution

It introduces a novel ultrasonic method employing pyridinium ionic liquid for preparing mesoporous silica with tunable porosity and microstructure.

Findings

Ultrasound increases pore size and volume.

Ionic liquid affects porosity and particle formation.

Sonogels have larger pores and lower surface area.

Abstract

Mesoporous silica matrices have been prepared via classic acid catalyzed and sono-catalyzed sol-gel routes. Tetramethoxysilan (TMOS) and methyl-trimethoxysilane (MTMS) were used as silica precursors, and N-butyl-3-methylpyridinium tetrafluoroborate ([bmPy][BF4]) was employed as co-solvent and pore template. The ionic liquid (IL) to silica mole ratio was varied between 0.007 and 0.07. Nitrogen adsorption-desorption and small-angle neutron scattering measurements were used to characterize the obtained materials. The ionic liquid played the role of catalyst that affected the formation of the primary xerogel particles, and changed the porosity of the materials. Ultrasound treatment resulted in microstructure change on the level of the colloid particle aggregates. In comparison with IL containing xerogels, the IL containing sonogels show increased pore diameter, bigger pore volumes and diminished surface areas.