Silica-based mesoporous materials derived from Ti containing layered polysilicate kanemite

Titanium containing layered disodium disilicates that are precursors of kanemite-like layered polysilicates with four-coordinated Ti species (Ti-kanemite) were successfully prepared by using mixed alkoxide solutions of silicon and titanium. According to this synthetic method, colloidal solutions without precipitates can be obtained at Si/Ti molar ratios above 300 under the basic conditions though titanium species are not stable in aqueous solutions under basic conditions. KSW-2-type mesoporous silicas containing TiO4 units were prepared by using Ti-kanemite with different Ti contents at room temperature through the reaction with hexadecyltrimethylammonium chloride, followed by mild acid treatment. Si/Ti molar ratio of the resultant Ti-KSW-2 without TiO6 species was as low as ca. 250 in the present system. All of the Ti containing KSW-2 with different Ti contents have high surface areas and pore volumes. Adsorption property of acetaldehyde molecules was investigated by using siliceous and Ti containing KSW-2; acetaldehyde molecules can be adsorbed very fast on the surfaces.