Zirconium nitride catalysts surpass platinum for oxygen reduction

Platinum (Pt)-based materials are important components of microelectronic sensors, anticancer drugs, automotive catalytic converters and electrochemical energy conversion devices 1 . Pt is currently the most common catalyst used for the oxygen reduction reaction (ORR) in devices such as fuel cells and metal–air batteries 2 , 3 , although a scalable use is restricted by the scarcity, cost and vulnerability to poisoning of Pt (refs 4 , 5 , 6 ). Here we show that nanoparticulate zirconium nitride (ZrN) can replace and even surpass Pt as a catalyst for ORR in alkaline environments. As-synthesized ZrN nanoparticles (NPs) exhibit a high oxygen reduction performance with the same activity as that of a widely used Pt-on-carbon (Pt/C) commercial catalyst. Both materials show the same half-wave potential ( E 1/2  = 0.80 V) and ZrN has a higher stability (Δ E 1/2  = −3 mV) than the Pt/C catalyst (Δ E 1/2  = −39 mV) after 1,000 ORR cycles in 0.1 M KOH. ZrN is also shown to deliver a greater power density and cyclability than Pt/C in a zinc–air battery. Replacement of Pt by ZrN is likely to reduce costs and promote the usage of electrochemical energy devices, and ZrN may also be useful in other catalytic systems.