Silica, Mesoporous Silica and Its Thiol Functionalized Silica Coated MgO and Mg(OH)2 Materials

Abstract

Silica (SiO2) and mesoporous silica (mSiO2) coated magnesium oxide composites were prepared based on hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) in presence of magnesium oxide nanoparticles (MgO-NPs) and cetyltrimethylammonium bromide (CTAB). Functionalization with thiolorganofunctional silane precursor was conducted onto the surface of mesosilica (Scheme 1). Silica coated MgO composites and its thiol functionalized material have been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope, Fourier transform spectroscopy (FTIR), ultra violet–visible spectra and thermal analysis (TGA). TEM analysis showed that the MgO nanoparticles were encapsulated into the SiO2 or mSiO2 precursors. XRD analysis reveals that magnesium oxide are exist into both forms, cubic MgO-structure and hexagonal Mg(OH)2-structure, which is converted into cubic structure upon silica coating. The mean crystallite size of MgO-NPs remains almost unchanged after coating with silica precursors. TGA and FTIR results indicated that the coated mesosilica layer around magnesium oxide nanoparticles has been successfully grafted by thiolorganofunctional silane groups.