Aerogels and xerogels of TiO2, V2O5, ZrO2, and Al2O3 with and without additives were prepared by hydrolysis of metal alkoxide. The aerogels and the xerogels were obtained by supercritical drying of the wet gels in ethanol and by drying at 90°C for 24 h in air. Catalyst activity of the gels for NO reduction with C3H6 were determined at 200-600°C in a fixed bed flow reactor. The highest NO conversion to N2 was obtained with Al2O3 aerogel catalysts, about 80% at 500°C. Al2O3-ZrO2 and ZrO2 have higher activities at lower temperatures. TiO2 and V2O5 have low activities although they have high oxidation activities. Catalyst activity of aerogels is higher than that of xerogels because of the higher effective diffusivity of reaction gas attributed to the high porosity and larger pore size.
|Number of pages||4|
|Journal||Journal of Non-Crystalline Solids|
|Publication status||Published - 1998 Apr|
- Reduction of NO
ASJC Scopus subject areas
- Ceramics and Composites
- Electronic, Optical and Magnetic Materials