Abstract: Three-dimensional ordered macroporous hybrid silica materials based on lacunary Keggin anions such as SiW ₁₁O₃₉^8- and γ-SiW ₁₀O₃₆^8- were prepared via sol-gel method as well as polystyrene templating technique. The structures of as-synthesized composites were characterized by UV diffuse reflectance spectra, FTIR, and solid-state MAS NMR. The results indicate that the primary Keggin structures remain intact in the hybrid materials, and chemical interaction exists between POM molecules and silica matrix. The porous structures of the composites were characterized by SEM and TEM, and their average pore diameters were (335±50) nm. The microporosity of the wall structure was evaluated by the nitrogen adsorption determination. The composites exhibit a photocatalytic activity to degrade aqueous malic acid under irradiation in the near-UV areas, and the leakages of the POMs from the hybrid materials are hardly observed during the process of photocatalysis.

Key words: Three-dimensional ordered macroporous hybrid materials, Polyoxometalates, Sol-gel, Polystyrene templating, Photocatalysis