Shear induced formation of patterned porous titania with applications to photocatalysis

Patterned macroporous titania (TiO2) materials have been synthesized via a shear-aligned rigid crystalline surfactant mesophase. The macropores inherit the hexagonal geometry of the water channels of the template. Scanning electron microscopy (SEM) and cut-section transmission electron microscopy (TEM) images show that the macropores templated by the sheared mesophase attain considerably greater alignment than pores templated by the nonsheared mesophase. The mean pore diameter, the crystalline size of TiO2 particles, and the photoactivity of the materials increase with the increase of water content in the template. The sheared TiO2 samples exhibit higher photocatalytic activity for the degradation of Rhodamine B than the corresponding materials synthesized in the nonsheared template. The improvement in photocatalytic activity of the sheared TiO2 materials is attributed to its higher photoabsorption efficiency and the patterned channels which facilitate the diffusion and transport of reactant molecules within the frameworks. Such patterned porous materials may have promise as advanced catalytic supports and photocatalytic materials.