Catalytic Activity of Zirconium Oxynitride Prepared by Reactive Sputtering for ORR in Sulfuric Acid

Abstract

Zirconium oxynitride (ZrO x N y ) prepared by the reactive sputtering method under O 2 and N 2 atmosphere was evaluated as a nonplatinum cathode catalyst for polymer electrolyte fuel cells. The ZrO x N y prepared at p Ar = 0.886 Pa, p N2 = 0.41 Pa, and p O2 = 1.7 mPa with a substrate temperature of 800°C during the film formation had a superior catalytic activity for the oxygen reduction reaction (ORR) in sulfuric acid. The onset potential for the ORR had a maximum of 0.8 V vs a reversible hydrogen electrode. The thin-film X-ray diffraction analysis and ionization potential measurement revealed that the ZrO x N y with a high catalytic activity for the ORR contained the Zr 2 ON 2 crystalline structure.