Abstract
The aim of this work is to prepare mesoporous silica materials with large pores by solgel method under mild conditions. The effect of several parameters of synthesis, such as catalyst nature, catalyst/silicon molar ratio, solvent, use of surfactant, and temperature, is reported. With large amount of HCl in the mixture of tetraethyl orthosilicate (TEOS), propanol and H2O, large pores of 93 angstrom are formed. In the presence of poly(propylene glycol) poly(ethylene glycol) poly(propylene glycol), the pore diameter of silica is improved and reached 122 angstrom. However, when CH3COOH is used in the sol-gel process, the maximum pore size obtained is around 54 angstrom, and increased to 78 angstrom by the presence of the surfactant. When the sol-gel temperature is raised to 60 degrees C a little amount of CH3COOH in propanol is enough to obtain large pores of 120 angstrom, which are even enlarged to 175 angstrom in the presence of surfactant. The use of propanoic acid in propanol under the same conditions allows the development of the largest pores, with a maximum in the pore size distribution of 289 angstrom.