FeCu-N6-C Diatomic Sites Catalyst for the Boosted Oxygen Reduction Reactions in Zinc-Air Batteries.

Due to the high catalytic activity and stability for oxygen reduction reaction, N-coordinated Fe-Cu dual-metal doped carbon material (FeCu-N-C) is considered to be one of the promising electrode materials for metal-air battery and fuel cells. Herein, FeCu-N-C dual-metal catalysts was synthesized by an adsorption-calcination strategy. The prepared FeCu-N-C exhibited high activity and stability both in alkaline and acidic media. In alkaline/acid medium, the half-wave potential reaches to 0.90/0.80 V, which is better than Fe-N-C catalyst. The power density for FeCu-N-C in zinc-air battery reaches to 220 mW cm^-2 and shows high electrochemical stability for more than 600 hours in charge/discharge cycles, much higher than 130 hours for Pt/C (40 %) and 100 hours for Fe-N-C. Density-functional theory calculations showed that the FeCu-N-C dual-metal catalysts got lower overpotential of 0.50 V than Fe-N-C (0.53 V), which improved the ORR activity. The results are helpful for the deep understanding of high-performance diatomic catalysts.