MAGNETIC MESOPOROUS SILICA NANOCOMPOSITES PREPARED WITH DIFFERENT SIZED Fe3O4: STRUCTURAL AND MAGNETIC PROPERTIES, CATALYTIC EFFECTS

Abstract

The magnetically separable mesoporous silica nanocomposites were successfully prepared through a one-pot method including the co-condensation of tetraethoxysilane (TEOS) as silica precursor and 3-mercaptopropyl trimethoxysilane (MPTMS) as functionalizing agent accompanied with hydrogen peroxide for oxidation of mercapto groups and triblock copolymers as structure directing agent in the presence of ferromagnetic and superparamagnetic Fe3O4 nanoparticles. By incorporating the superparamagnetic (near zero coercivity) Fe3O4 nanoparticles to the mesoporous silica (SBA-15) and functionalizing with sulfonic acid groups instead of ferromagnetic Fe3O4 nanoparticles, we developed versatile nanocomposite having superior properties with respect to magnetism, catalysis and porosity. Reducing the particle size of Fe3O4 from the ferromagnetic regime to the superparamagnetic regime, the pore closure could be eliminated because of the more open pore as well as saving magnetic properties.