Room temperature ionic liquids as templates in the synthesis of mesoporous silica via a sol–gel method

With various RTILs as templates, amorphous mesoporous silica gel materials were synthesized according to a proper sol–gel method. The materials display pore diameter of 3–12 nm, pore volume of 0.4–1.3 cm3/g and BET surface area of 300–800 m2/g. The effect of variations of the anions and cations of ILs, the alkyl chain length on imidazolium cation and IL concentration in the reaction system on the pore structure and thermal stability of the silica gel materials was preliminarily studied. It is suggested that, the pore size of silica gel can be tuned by variations of ILs and IL content. The different kind of the anions of ILs could largely impact the properties of the obtained silica gel materials. The mesoporous silica gels with 1-alkyl-3-methylimidazolium tetrafluoroborate as templates possessed larger pore sizes of 5–12 nm and higher thermal stability than the materials obtained with other ILs as templates.