Exfoliation and reassembling route to mesoporous titania nanohybrids

Abstract

To fabricate mesoporous photocatalysts with delaminated structure, the exfoliated layered titanate in aqueous solution was reassembled in the presence of anatase TiO 2 nanosol particles to induce a great number of mesopores and eventually a large surface area of TiO 2 photocatalysts. No (0/0) peaks corresponding to the layered titanate appear in the X-ray diffraction patterns of the reassembled hybrids, which suggests that the titanate nanosheets were randomly hybridized with TiO 2 nanoparticles without any restacking into the layered phase. According to the high-resolution transmission electron microscopy images of these nanohybrids, the randomly oriented titanate nanosheets can be seen clearly along with TiO 2 nanosol particles with spherical images, indicating that the exfoliated sheets are indeed incorporated with anatase nanosol particles to form porous materials. From N 2 adsorption-desorption isotherms, these nanohybrids are fairly high in specific surface area and in mesoporosity for effective photocatalysis (S BET = ∼190 m 2/g, pore size = ∼6 nm). The photocatalytic activity of the present mesoporous nanohybrids is superior to that of TiO 2 nanosol particles or layered titanate alone in terms of the degradation of organic pollutants such as 4-chlorophenol, methyl orange, and methylene blue. © 2006 American Chemical Society.