Preparation of spherical MCM-41 in water-acetone media

The mesoporous silica nanoparticles with controlled morphologies were prepared in water-acetone solvent. Further investigations showed that prolonging the reaction time led to an increase of the cell parameter; increasing the amount of ammonia solution resulted in an increase of pore diameter and decreases of pore volume and specific surface area, however, increasing the amount of CTAB made the pore volume and the specific surface area increased while the pore diameter almost kept intact. Interestingly, it is proved that the mesoporous silica obtained at the system composition of n(TEOS):n(CTAB):n(NH₃(H₂O): n(Acetone):n(H₂O)=1:0.07:1.4:20:144 composed of virtual mixed nanospheres including solid and hollow, which were of regular and uniform size, being approximately 500 nm. Solid sphere has obvious radial pores, whereas hollow sphere has a mesoporous shell perforated by hexagonally-arrayed cylindrical nanochannels.