Synthesis and structural and photocatalytic properties of TiO_2/montmorillonite nanocomposites

摘要

TiO_2 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 TiO_2 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/TiO_2 sol. X-ray diffraction measurements of the samples reveal that in the course of composite formation, TiO_2/montmorillonite intercalation structures containing the anatase phase of TiO_2 were formed. The specific surface areas of the samples determined by nitrogen adsorption ranged from 120 to 290 m~2/g. TiO_2/montmorillonite composites prepared at pH = 1 have higher specific surface areas than those prepared using the sol with pH = 4. The catalytic properties of TiO_2/montmorillonite composites were tested in the photooxidation of phenol. The TOC data presented show that the photocatalytic efficiency of TiO_2 can be significantly enhanced by intercalation in montmorillonite support.