Gas phase synthesis of titania with aerogel character and its application as a support in oxidation catalysis

Abstract

Titania materials with structures resembling aerogels are presented in the current contribution. In contrast to the classical routes the aerogel-like TiO2 materials discussed here are prepared exclusively by a high-temperature aerosol process. Thus, the titania particles forming the network are highly pure, highly crystalline and their surfaces are free of any additives. It is shown that the structure of the materials (particle-size, porosity, surface area, crystallinity, and phase composition) depends on a complex interplay of different parameters (temperature gradients, precursor concentration, residence time, etc.). However, the understanding of those correlations enables the preparation of tailor made titania materials with aerogel-like structure. The size of the primary, nanocrystalline particles can be varied systematically from 13 nm to 70 nm. The composition regarding the two different crystalline phases anatase and rutile can be adjusted as an independent parameter. Finally, the aerogel-like TiO2 materials were loaded with Au clusters and the activity in oxidation catalysis was investigated.