Zirconium-Based Compounds for Cathode of Polymer Electrolyte Fuel Cell

Zirconium-based compounds, such as , have been investigated as a cathode of polymer electrolyte fuel cells. was prepared using radio-frequency (rf) magnetron sputtering under an with heating the substrate. The solubility of deposited at was less than in at under atmospheric condition, indicating that had a high chemical stability in acidic media. The effect of the heat-treatment during the film deposition on the catalytic activity for oxygen reduction reaction (ORR) and the properties of has been examined. The ORR current density on deposited at a substrate temperature of was times greater than that at . The dependence of both the ORR current density at and the apparent activation energy of the ORR at on the substrate temperature changed near . The crystalline structure of also changed near . In addition, the catalytic activity for the ORR increased with the increasing crystallinity and decreasing ionization potential of the specimens. Therefore, the crystalline structure, the crystallinity, and the ionization potential might affect the catalytic activity for the ORR.