III International Conference

PP-II-97NANOSTRUCTURED COMPLEX OXIDES FOR CATALYTIC COMBUSTION ANDFUEL CELLS APPLICATIONSParvulescu V., Somacescu S., Tanasescu S., Todorova S. 1 , Kadinov G. 1 , Su B.L. 2Institute of Physical Chemistry, Spl. Independentei 202, 060021 Bucharest, Romania1 Institute of Catalysis, Bulgarian Academy, Acad. G. Bonchev St., Block 11, Sofia, Bulgaria2 Laboratoire de Chimie des Matériaux Inorganiques, The University of Namur (FUNDP), 61rue de Bruxelles, B-5000 Namur, BelgiumE-mail: vpirvulescu@chimfiz.icf.roMesoporous ZrO 2 - TiO 2 -Y 2 O 3 complex oxides which have utility as electrode material insolid fuel cells (SOFCs) have been synthesized, characterized and used as catalysts forcombustion of hydrocarbons. The obtained oxides were characterized by XRD, TGA,adsorption-desorption of N 2 , TEM, SEM, IR and UV-Vis spectroscopy, XPS. The materialspresent an ordered mesoporous structure and high surface area. Stability of the porousstructure is observed after calcinations at 673 K and partial breakdown of structure occursafter 873 K by crystallization of oxides. ZrO 2 - TiO 2 -Y 2 O 3 oxides were modified with Ce, Nbor W and their role on catalytic activity in oxidation processes were edified.The reactions that occur at the fuel-cell electrodes are obviously at least partiallycatalytic, so the choice of electrode materials will affect cell performance and fuel sensitivity.The electrochemical reaction is a redox process with a nonconventional oxygen source [1].Many properties of the materials evidenced in nanotechnology involve in the solids largesurface areas, regular and high porosity at the nanometer scale. In nanometer-sized particles,the ratio of the number of atoms in the surface to the number in the bulk is much larger thanfor micrometer-sized materials, and this can lead to novel properties.In this paper nanostructured mesoporous ZrO 2 -TiO 2 -Y 2 O 3 complex oxides aresynthesized by surfactant-assisted preparative chemistry, characterized and used as catalystsfor oxidation of volatile organic compounds. The oxides, with various titania content (8 % -40 %), were prepared using various surfactants (Brij 30, polyoxiethylene tridecylether, blockcopolymer P123) as structure directing agents and precursors of oxides (zirconium chloride,titanium isopropoxide and yttrium nitrate). Urea was used as hydrolyzing agent and variouspromoters (CeO 2 , NiCo, NiCu, NiFe) were added to increase the performances, as catalystand anode, of the obtained materials. All the materials were prepared at room temperature byvigorous mixing of surfactants, water and precursors. The resulted gels were sealed and heatedin autoclave at 253 K. The solids were filtered, washed, dried and calcined in air al 823 K.339