Synthesis of ordered mesoporous bifunctional TiO2–SiO2–polymer nanocomposites

Abstract

Ordered mesoporous bifunctional TiO₂–SiO₂–polymer nanocomposites have been synthesized via the direct triblock-copolymer self-assembly route using soluble phenolic resins as polymer precursors, tetraisopropyl titanate as a titanium precursor, tetraethoxysilane as a silica precursor, and Pluronic F127 as a template. The XRD, N₂ sorption isotherms and TEM techniques reveal that the nanocomposites have a highly ordered 2-D hexagonal mesostructure, high surface areas (∼700 m²/g), large pore volumes (∼0.8 cm³/g) and large pore diameters (∼8.0 nm). These analyses, together with the XPS and FT-IR techniques, indicate that the pore walls are composed of polymer, silica and Ti species. Organic polymers and inorganic solids are homogeneously dispersed inside the pore wall, and Ti species are tetrahedrally incorporated into silica frameworks to compose the inorganic compounds. The organic polymer and tetrahedrally coordinated Ti species contribute bifunctionality of hydrophobicity and catalytic centers to the silica matrix. Both the polymer and titanium contents can be tuned by adjusting the amount of each raw material in the initial solution.