Thermal influence on the structure and photocatalytic activity of mesoporous titania consisting of TiO₂(B)

Mesoporous titania was synthesized using the evaporation-induced self-assembly method. The sample calcined at 300 °C had a wormhole-like structure with uniform mesopores consisting of TiO₂(B). The sample calcined at 350 °C consisted of a mixed phase of TiO₂(B) and anatase; however, the mesoporous structure showed little change compared with that of the sample calcined at 300 °C because the phase transition from TiO₂(B) to anatase has a displasive phase transition mechanism with no atomic diffusion and accompanying no crystallite growth. When calcined above 400 °C, the mesoporous structure collapsed, and aggregates of anatase nanoparticles that were highly crystalline and had high specific surface area were obtained because the mesopores at several nm intervals inhibit anatase particle growth. Samples calcined at 300, 350, 400, and 450 °C showed 1.5, 2.4, 2.5, and 1.8 times higher photocatalytic activity than commercial titania P-25 in acetic acid decomposition.