Alumina gels are known to be good catalysts for the selective reduction of NOx using hydrocarbon under an oxidizing atmosphere. The effects of galia-addition on the microstructure and catalytic activity of alumina aerogels were investigated. Aerogels containing 0-66 wt% Ga2O3 were prepared by hydrolyzing Al(sec-C4H9O)3 (ASB) in an ethanol solution, adding Ga(NO3)3 dissolved in H2O, followed by supercritical drying. The catalytic activity of aerogel catalysts containing 38-51 wt% Ga2O3 was higher than pure alumina at low temperatures, 450-550°C, but decreased when the Ga2O3 content was 66 wt%. The amount of desorbed NH3, which is related to the catalytic activity, increased with increasing Ga2O3 content, but the fraction of mesopores, 20-30 nm in diameter, decreased when Ga2O3 content >60 wt%. These results show that changes in the gel microstructure caused by Ga2O3 addiction affect the catalytic activity.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry