Morphological control of mesoporous materials using inexpensive silica sources

Mesoporous silicas with different morphologies have been selectively synthesized from an aqueous reaction mixture consisting of an inexpensive sodium silicate, mixed templates and concentrated HCl solution. The mesoporous spheres from sodium silicate exhibit a narrow distribution of mesospores, high specific surface area and pore volume, compared with those from traditional TEOS as the silica source. Effects of molar ratios of Triton X-100/CTMAB and the stirring upon the macrostructures of mesoporous silica synthesized using sodium silicate as silica precursor have also been examined. Shape transition of rod-sphere-tortuous rod could be obtained by changing the molar ratios of Triton X-100/CTMAB. The synergetic effects of sodium silicate and the mixed surfactants are thought to determine the formation of the morphologies of mesoporous silicas. It is shown that a static condition instead of stirring is favorable for the formation of silica spheres in the present synthesis.