摘要
The highly ordered titanium dioxide (TiO 2 ) porous films was fabricated by a single-step assembly method in which the fabrication of opal structure and the infiltration of TiO 2 sol particles into the voids between templates were carried out simultaneously. The polystyrene microspheres with diameters ranging between 480 and 1000 nm were used as the template, and titanium tetrabutoxide, a precursor of TiO 2 , was prepared in an acidic solution to fill the voids between the template microspheres during the formation of opal structure. The properties of the highly ordered TiO 2 porous materials were examined by scanning electron microscopy (SEM), thermogravimetry (TA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and specific surface area analyzer. Thermal analyses showed that polystyrene can be completely removed at 425 °C and the phase transformation of TiO 2 from amorphous to crystalline anatase occurred at 360 °C. SEM images clearly demonstrated that these films have a highly ordered three-dimensional porous structure arranged mainly in hexagonal orientation. The XRD patterns indicated that the crystalline phase of TiO 2 is mainly anatase with crystallite sizes of 7.0-9.7 nm. In addition, the ratio of rutile to anatase increased slightly with the increase in hole diameters of the ordered TiO 2 porous films. The specific surface areas of the ordered TiO 2 porous film ranged between 59 and 84 m 2 g -1 , and the determined adsorption pore sizes in walls between templates were in the range 5.1-6.0 nm, which indicates that the fabricated TiO 2 film is a macrostructured mesoporous material. The ordered TiO 2 porous films showed high photocatalytic activity in degradation of methylene blue (MB) solution. The degradation rate increased linearly with the increase in hole diameters of the TiO 2 films ranging between 480 and 1000 nm. Results obtained in this study clearly show the feasibility of using one-step method to fabricate the highly ordered TiO 2 materials as potential supports for heterogeneous catalysis. © 2007 Elsevier B.V. All rights reserved.