Abstract:

Titanium dioxide has been considered to be one of the most effective and environmental friendly photocatalytic material. It has been widely used in photocatalytic degradation of various pollutants. As we known, an anatase crystal form typically obtained by high temperature heat treatment (>600℃), usually shows higher catalytic activity. In order to further improve the catalytic efficiency, we prepared TiO₂ with a non-supercritical drying method to form a high specific surface area aerogel structure, along with an increased active contact site. However, with the inevitable of internal pores collapse in the process of high temperature crystallization, a large amount of porous structure and specific surface area is reduced. Here, to enhance the photocatalytic activity of titania, we propose a synergistic strategy to fabricate a porous titania structure with a high specific surface area. It was crystallized at a lower temperature (120℃) in a low-boiling solvent (ethanol, acetone, etc.). The lattice structure was identified by X-ray diffractometry; specific surface area (over 300 m²/g) of our sample was also measured through BET test; in the subsequent photocatalytic degradation test, the photocatalytic degradation efficiency of fabricated TiO₂ is proved to be more excellent than P25 powder. By a freeze-drying/mild crystallization method, a high-specific surface area and high catalytic activity TiO₂ aerogel was synthetized. This study provides some insights in the combining of crystallization and high specific surface area of titanium dioxide photocatalysis.

Key words: TiO₂ aerogel, Non-supercritical drying, Low temperature crystallization, Photocatalysis