Development of Zirconium Based Non-Platinum Cathode for Polymer Electrolyte Fuel Cell

摘要

Zirconium based compounds (ZrO_xN_y) have been investigated as a new cathode of polymer electrolyte fuel cells without platinum. The ZrO_xN_y film were prepared by the radio frequency magnetron sputtering method under Ar + O_2 + N_2 atmosphere with heating the sputtered material. The effect of the heat treatment on both the catalytic activity for the oxygen reduction reaction (ORR) and the properties of ZrO_xN_y has been examined. The solubility of ZrO_xN_y was less than 5×10~(-8) mol dm~(-3) in 0.1 mol dm~(-3) sulfuric acid at 30 ℃ under atmospheric condition. This indicated that ZrO_xN_y had a high chemical stability in acidic media. The ORR current density on ZrO_xN_y which was heated at 800 °C was about 30 times larger than that on ZrO_xN_y deposited at 50 ℃. It was found that heating the sputtered material during the deposition was very effective to increase the catalytic activity for ORR. The higher temperature of heat treatment caused the change of crystalline structure and the increase of the crystallinity of ZrO_xN_y.