Abstract: The montmorillonite composite structure samples were prepared using a hydrolysation-intercalation composite method with TiOSO₄·2H₂O as a precursor of TiO₂ nano-particles and montmorillonite as substrate by controlling the pH value of the montmorillonite suspension. The changes of the structure, phase and crystal size of the samples were characterized by X-ray diffraction method. The results show that the pH value of montmorillonite suspension has a significant influence on the hydrolyzation of TiOSO₄·2H₂O, so the composite structure of hydrated- titanium-oxide/montmorillonite is affected. When the pH value of montmorillonite suspension is 0.5, the poly-titanium-ions are with the lower electrovalence and extent of polymerization and easily intercalate the interlayer space of montmorillonite, moreover, the structural layers of montmorillonite are separated best. The crystal size of anatase in the TiO₂/montmorillonite composite samples calcinated at 700℃ is smallest and reaches 13.4 nm. After calcination at 1100℃, the relative content of anatase in the composite structure reaches 35%. Compared with pure TiO₂ nano-particle sample, TiO₂/Montmorillonite composite sample has a higher phase transition temperature from anatase phase to rutile phase and smaller crystal size of TiO₂. Montmorillonite structure layer has a significant blocking effect on the TiO₂ phase transformation and grain growth.

Key words: poly-titanium-ion, montmorillonite, anatase, composite structure