Synthesis of sol-gel pyrophyllite/TiO2 heterostructures: Effect of calcination temperature and methanol washing on photocatalytic activity

Abstract

We successfully synthesized an efficient photoactive pyrophyllite/TiO2 heterostructures using a sol-gel route at ambient temperature. The samples were prepared by exfoliation of a pyrophyllite layered-type clay by TiO2. The prepared samples exhibited strong photocatalytic activity for the degradation of phenol. The heterostructure PTi750 (S-BET = 16.58 m(2)/g) calcined at 750 degrees C, in which the mixed phases of anatase and rutile exist (52.2% anatase/10.7% rutile), showed the highest photocatalytic activity against commercial TiO2 Aeroxide P25. The methanol washed PTi750 was 5 times faster than the corresponding unwashed sample; phenol was totally degraded with a TOC reduction of 89.2%. The materials have been characterized by: X-ray diffraction (XRD), Diffuse reflectance UV-vis spectrophotometry (UV-Vis DRS), scanning electron microscopy (SEM) and BET specific surface area.