Electrochemically induced surface modification of titanols in a `nanoglued' titania aerogel–silica aerogel composite film

Titania aerogel, thermally processed into its anatase form, has been bound as submicrometer particles to an electrode with silica sol. The resulting composite gel is supercritically dried to create a titania–silica composite aerogel film on the conducting substrate. Titania aerogel particles present in the mesoporous film are electrochemically addressable. In organic electrolyte containing isopropanol and added water, the electrochemical response negative of the flatband potential of TiO2 indicates that electrogenerated reactants (hydroxides and isopropoxides) induce condenzation reactions with surface titanols (Ti–OH). The data suggest that titania aerogels can be electrochemically modified in a controllable way with a wide variety of compounds that have reducible –OH moieties.