Plasma-electrolytic formation, composition and catalytic activity of manganese oxide containing structures on titanium

In the present work, we report the data about formation of TiO2-rutile or TiO2 and Mn2O3, Mn3O4 containing oxide structures on titanium in aqueous electrolytes by means of plasma-electrolytic deposition. The layers formed are characterized by X-ray diffraction, electron probe microanalysis and scanning electron microscopy methods. The PEO coatings on titanium formed in sodium tetraborate solution contain the TiO2 Stabile rutile modification that is important when utilizing such a structure as a catalyst carrier. Manganese acetate adding into the electrolyte leads to formation of layers that contain Mn2O3, Mn3O4 and TiO2-rutile in outer region. The manganese content in the surface layer depends on the formation conditions as well as on manganese acetate concentration in the electrolyte. Catalytic activity of the layers in CO -> CO2 reaction is studied in the static and flow conditions. The manganese-containing layers obtained possess the catalytic activity in CO -> CO2 oxidation reaction at the temperature range of 250-350 degrees C. The catalytic activity depends on the concentration and surface distribution of manganese as well as on the layers morphology. (c) 2005 Elsevier B.V. All rights reserved.