A facile approach for the tunable wormlike or ordered pore morphology of mesoporous silica: Effect of catalyst types and polyethylene glycol

作者：Lai Sun Mou^*; Lai Hui Yu; Chou Mu Yu

来源：Microporous and Mesoporous Materials, 2014, 196: 31-40.

DOI：10.1016/j.micromeso.2014.04.043

• Mesoporous silica
• Catalyst
• Polyethylene glycol
• Morphology

Two different basic catalysts, NaOH and NH4OH, to the formation of mesoporous silica with completely different pore morphology at the same mole concentration with or without polyethylene glycol (PEG) were investigated. NaOH catalyzed system seemed to have a more ordered structure and larger particle size than NH4OH catalyzed system. The addition of PEG tended to promote the charge matching probability for silicate oligomers and micelles, which resulted in the more ordered pore morphology for NH4OH system. With increased ammonia concentrations, the pore morphology of disordered wormlike structure was transformed into ordered MCM-41 type mesoporous structure with particle dimension in a few tenths of nanometer to hundred nanometer. With the addition of PEG, at low ammonia concentration, the mesoporous pores became more orderly arranged as well. However, the effect of PEG on the pore and particle morphology of the NaOH catalyzed system was less evident than that of the NH4OH system. The catalyst types were also investigated at the same pH to contrast the significance of catalyst effect on the preparation of mesoporous silica, which was often neglected in the literature. NaOH catalyzed system still indicated a more ordered wormlike structure and slightly larger particle size than NH4OH catalyzed system. The XRD (X-ray diffraction) results and N-2 adsorption-desorption isotherms were in agreement with the TEM (Transmission electron microscope) morphology. The significance of two different catalysts with the addition of PEG in tuning pore morphology was justified.

• 出版日期2014-9-15