A tungstophosphate derivative, (Bu₄N)₃PW₁₁O₃₉[O(SiOH)₂] (TBAPW₁₁Si₂), with Si-OH groups on the surface was grafted on mesoporous TiO₂ synthesized by an evaporation-induced self-assembly method. Such TBAPW₁₁Si₂/TiO₂ mesoporous hybrid materials were characterized by IR, XRD, N₂ adsorption- desorption, TEM and ICP-AES techniques. It was shown that the covalent linkage between TBAPW₁₁Si₂ and TiO₂ formed by condensation of Si-OH on TBAPW₁₁Si₂ with Ti-OH on TiO₂. Enough Ti-OH groups on TiO₂ surface and the calcination at a certain temperature were necessary for the condensation. Compared with TiO₂ support, the hybrid samples had a little higher crystallinity of anatase, but the surface area, pore volume and pore size decreased as TBAPW₁₁Si₂ loading increased. In the degradation of methyl orange, these hybrid samples exhibited higher photocatalytic activities than anatase TiO₂ support, and their activities were even comparable with that of Degussa P25 with much higher crystallinity, which can be mainly attributed to a synergistic effect between polyoxometalate and TiO₂.

Key words: TiO₂, polyoxometalate, grafting, mesoporous hybrid materials, photocatalysis