Electrochemical Reduction of TiOx at Room Temperature in Ionic Liquids

The reduction of titanium oxide was achieved in ionic conducting electrolytes on oxidized titanium foils and on titanium oxide particles in a packed bed electrode configuration. The surface of a titanium foil oxidized in air at 550C for 140 hrs was studied with cyclic voltammetry. The voltammetry showed a series of shallow waves in the negative potential region corresponding to reduction reactions occurring on the surface oxide. Changes observed in subsequent cycles clearly indicated that the oxide had undergone significant changes. To establish that titanium metal was obtained an experiment was run using TiO 2 particles in a packed bed configuration where no titanium metal was available to give false analytical signals. After the particles were exposed to conditions which were determined, from the voltammograms on the oxidized Ti foil, to lead to metallic titanium the particles were examined with x-ray photoelectron spectroscopy (XPS) to determine the presence of elemental titanium metal. A 20% conversion to elemental titanium was observed. Further experiments were carried out on the oxidation/reduction behavior of Ti +3 and Ti +4 ions in the ionically conducting electrolytes.