Preparation, characterization and catalytic properties of singly and doubly titanium-modified mesoporous silica gel

A series of titanium-modified mesoporous silica gel have been synthesized using tetrabutyl titanate. The samples were characterized by nitrogen adsorption–desorption, FT-IR and Raman spectroscopy, as well as by solid state diffuse reflectance UV–VIS spectroscopy. Physicochemical characterization of the materials showed that Ti atoms were part of the framework of silica gel, and it was probably in a tetrahedral coordination for low Ti contents. The resulting titania modified the inner walls of the mesoporous silica gel after hydrolysis and calcination. Actually, the titanium precursor reacted and condensed with the active silanol groups on silica gel via Si–O-Ti bonds. In addition, the titanium-modified mesoporous silica gel showed distinct activity behavior in the catalytic oxidation of cyclohexene and styrene with hydrogen peroxide as oxidant.

Research Highlights
► Titanium-modified silica gel with the meso-structure was synthesized by a facile way.
► Ti-containing silica gel has larger pore volume and well-defined aperture sizes.
► Titania existed as a thin layer on the channel surface of mesoporous silica gel.
► Singly and doubly Ti-modified silica gel exhibits effective catalytic activity.