Synthesis and structural and photocatalytic properties of TiO2/montmorillonite nanocomposites

TiO2 was prepared by sol-gel method and the sol obtained was used for heterocoagulation of Na-montmorillonite at several different mass ratios, resulting in nanocomposites of various compositions. The TiO2 content of the samples ranged from 20% to 75% (m/m). Heterocoagulation was performed using a strongly acidic (pH = 1) as well as a weakly acidic (pH=4) Ti(OH)(4)/TiO2 so]. X-ray diffraction measurements of the samples reveal that in the course of composite formation, TiO2/montmorillonite intercalation structures containing the anatase phase of TiO2 were formed. The specific surface areas of the samples determined by nitrogen adsorption ranged from 120 to 290 m(2)/g. TiO2/montmorillonite composites prepared at pH = 1 have higher specific surface areas than those prepared using the sol with pH =4. The catalytic properties of TiO2/montinorillonite composites were tested in the photooxidation of phenol. The TOC data presented show that the photocatalytic efficiency of TiO2 can be significantly enhanced by intercalation in montmorillonite support. (C) 2005 Elsevier B.V. All rights reserved.