Temperature control in the synthesis of cubic mesoporous silica materials

The cubic mesoporous silica MCM-48 materials have been synthesized by temperature control, and the properties of samples were investigated by using XRD, HREM and N₂ adsorption-desorption techniques. XRD results show that the mesophases synthesized at low temperature (≤75 °C) have a poorly ordered hexagonal structure, while hydrothermal treatment at higher temperature (≥95 °C) led to cubic MCM-48 mesophases. The effect of temperature on different mesophases can be due to the polymerization and condensation of silicate species at different temperatures, which results in the formation of curvatured hexagonal or cubic phase. HREM and N₂ isotherms of MCM-48 materials indicates well-ordered three-dimensional meso-channels.