Compositional effects of bimodal mesopore silica synthesized by a base-catalyzed ambient pressure sol-gel processing

The effects of tetraethylorthosilicate (TEOS) concentration and TEOS/surfactant molar ratio on the synthesis of bimodal mesopore silica (BMS) were studied. It was found that the BMS silica can be synthesized in a wide range of component concentration and its secondary mesopore size is more sensitive to the change of precursor concentration than its primary mesopore size and the secondary mesopore volumes can be up to 2.0 or more times as large as the primary mesopore volumes. The controllability of the bimodal mesopore size distributions, in particular the secondary mesopore size of BMS silica is of great interest to catalysis because they greatly facilitate mass transport to the primary mesopore.