Aerogels offer interesting opportunities for catalysis due to their unique morphological and chemical properties. These properties originate from their wet-chemical preparation by thesolution-sol-gel (SSG)method and their subsequent liberation from the solvent viacritical-point dryingorsupercritical(orhypercritical)drying (SCD). Due to the “structure-preserving” ability of SCD, the usually oxidic (or metallic) aerogels are solids of high porosity and specific surface area.