Abstract
The fabrication and characterization of highly ordered porous structure has recently received much attention because of its wide variety of possible applications to sensors, high-performance photocatlysts, solar cells, and photonic band gap materials. The purpose of this research is to use sol-gel and dipping methods to fabricate the three-dimensional ordered porous TiO2 structure with high specific surface area. The TiO2 sol solution was directly mixed with the polystyrene, to fabricate order porous materials so that the infiltration of titania colloids and the fabrication of opal structure were carried out at the same time. Titanium tetrabutoxide (Ti(OC4H9)4), a precursor of TiO2 was prepared in an acidic solution to fill the voids between the template microspheres. The polystyrene microspheres ranging between 480 and 1000 nm in diameter were used as the template. Results showed that found that the volume ratio of PS/TiO2 sol is an important factor influencing the fabrication of ordered structures and the optimized ratio was 5/4 for 480 nm, 5/4 for 600 nm and 5/2 for 1000 nm PS in the in the presence of 0.1 mM CTAC. The TGA and DSC analyses showed the complete removal of polystyrene at 424 □C and the phase transformation of TiO2 from amorphous to crystalline anatase at 363 □C. The SEM images clearly showed the highly ordered porous TiO2 structure arranged mainly in hexagonal orientation. The XRD pattern indicates that the crystal phase of TiO2 is anatase with crystallite size of 7.98 nm. The specific surface areas of the fabricated ordered TiO2 structure were in the range of 59-84 m2/g. Results obtained in this study clearly show the feasibility of using one-step sol-gel method to fabricate the highly ordered macroporous TiO2 materials.