The catalytic activity of hybrid organic-inorganic silica glasses doped with the ruthenium species tetra-n-propylammonium perruthenate (TPAP) in the aerial oxidation of alcohols to carbonyl compounds, either in toluene or in dense-phase CO2, substantially increases with time several months after the xerogels' preparation, yielding the most active ruthenium-based aerobic-oxidation catalysts reported thus far. The doped sol-gels are living materials, and an explanation of the observed reactivity enhancement is given, which is thought to have general validity for future applications to a wide variety of relevant heterogeneous processes.