The structure and morphology control of mesoporous silica under acidic conditions

The synthesis and crystallization mechanism of various mesoporous molecular sieves with varying morphology have been studied by the methods such as X-ray diffraction (XRD), scanning-electron microscope (SEM), elemental analyses and N2 adsorption-desorption. By adjustment of the synthesis conditions, two types of mesoporous materials with highly resolved XRD patterns and particular morphologies were obtained using cetyltriethylammonium bromide (CTEABr) in the presence of HCl. The g value of lyotropic crystal mesophases was decreased with heating, which led to formation of larger curvature mesophases. The large g value lyotropic crystal mesophases were formed with increase in the surfactant concentration and with decrease in the Si/surfactant ratio.