Palladium–iridium nanowires for enhancement of electro-catalytic activity towards oxygen reduction reaction

•Palladium–iridium nanowires were synthesized via a facile hydrothermal process.•The nanowires show high uniformity in diameter (1.5–2.0 nm) and rough surface.•The Pd–Ir nanowires display high ORR activity and durability in acid media.•Electron transfer numbers for oxygen reduction reaction are close to four.

In this work, palladium–iridium nanowires with a Pd/Ir atomic ratio of 2/1 are synthesized through a facile hydrothermal method. Transmission electron microscopy images show that the palladium–iridium nanowires have a uniform diameter below 2 nm and a rough surface with many atomic steps. The electro-catalytic performance of the carbon supported palladium–iridium catalyst towards oxygen reduction reaction has been examined in 0.1 M HClO4 solution. The carbon supported palladium–iridium catalyst displays comparable catalytic activity but much higher durability in comparison with those of the commercial carbon supported platinum catalyst. The excellent electro-catalysis might be attributed to the high accessible area, rough surface and iridium introduction. The work demonstrates that palladium–iridium nanocrystals are promising electro-catalysts for oxygen reduction electro-catalysis in acid media.

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