Characteristics of vanadia-titania aerogel catalysts for oxidative destruction of 1,2-dichlorobenzene

Abstract

Vanadia-titania catalysts prepared by a sol-gel method and by supercritical drying showed a very high activity and thermal stability for gas phase oxidation of 1,2-dichlorobenzene (DCB) in the range of 150-600 degrees C. The selectivity for carbon oxides was kept over 95% unless the reaction temperature was relatively low (<200 degrees C). The conversion was maintained over 90% at above 350 degrees C with a residence time of less than 0.05 s and deactivation was not observed during the 48 h of operation at 450 degrees C. The surface structure of vanadia played a critical role on the catalytic activity, but the structure of crystalline titania was revealed to have exclusive dependency. For the vanadia-titania catalysts with the inherent characteristics of aerogels such as high specific surface area and chemical homogeneity, little bulk vanadia was observed and catalytic activity was maintained or improved due to the formation of surface mono- and polyvanadates after repeated reactions. (C) 2006 Elsevier B.V. All rights reserved.