Preparation of titania material with controlled macro-mesopores by phase separation

The titania material with macro-mesopores was prepared by sol-gel route and phase separation under strong acid conditions. The influence of HNO₃ concentration on the structure of TiO₂ was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer-Emmet-Teller (BET). The results showed that the specific surface area and pore volume of TiO₂ decreased with the increase of HNO₃ concentration, and the phase transformation of TiO₂ changed. When HNO₃ concentration was 20%, the pore collapsed and the pore volume and specific surface area were deteriorated sharply. The morphology of macroporous structure was related to HNO₃ concentration and the titania material had well-defined bicontinuous macropores skeletons when the acid concentration was 5%, while the titania material had circular pores skeletons when HNO₃ concentration was 10%.