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

Abstract

The magnetically separable mesoporous silica nanocomposites were successfully prepared through a one-pot methodincluding 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 triblockcopolymers as structure directing agent in the presence of ferromagnetic and superparamagnetic Fe3O4 nanoparticles. Byincorporating the superparamagnetic (near zero coercivity) Fe3O4 nanoparticles to the mesoporous silica (SBA-15) andfunctionalizing with sulfonic acid groups instead of ferromagnetic Fe3O4 nanoparticles, we developed versatilenanocomposite having superior properties with respect to magnetism, catalysis and porosity. Reducing the particle size ofFe3O4 from the ferromagnetic regime to the superparamagnetic regime, the pore closure could be eliminated because of themore open pore as well as saving magnetic properties.