PREPARATION AND CHARACTERIZATION OF PLATINUM CERAMIC COMPOSITE POWDERS AND THIN-FILMS

Pt-ceramic (TiO2, ZrO2, and ZrO2-5 mol% Y2O3 (PSZ)) composite powders were prepared by liquid-phase reaction. These composite powders show highly functional properties such as the following. The sintered films of these powders are good metallic conductors. The resistivity of the Pt-PSZ film at room temperature is about 1.5 X 10(-5) OMEGA.cm, which is almost comparable to that of pure platinum (1.05 X 10(-5) OMEGA.cm). This film shows excellent cathodic oxygen reduction. The overpotential for the oxygen reduction at 750-degrees-C is less than 20 mV even at a high current density of 0.1 A/cm2. The Pt-TiO2 composite powders have highly catalytic activity for the reduction of NO gas.