It is shown that HPA/silica composite catalysts are much more active than HPA/Polyaniline composites in the reaction of isopropanol decomposition. The catalysts prepared using ethyl silicate 40 as a silica precursor showed better texture properties than those prepared using tetraethoxysilane but activities of the two families appeared to be similar. The use of 3-aminopropyltriethoxysilane, as an additive promoted the formation of a porous texture but this had no positive effect on the catalyst's activity.