A durable half-metallic diatomic catalyst for efficient oxygen reduction

Single atom metal-nitrogen-carbon materials have shown immense potential for the oxygen reduction reaction (ORR) while the development of durable catalysts with high reactivity remains a great challenge. Herein, by rationally designing a diatomic catalyst Fe/Zn-N-C based on theoretical screening, we propose a unique half-metallic electronic structure induced by cooperation of Fe and Zn. This structure populates spontaneous spin-polarized conduction electrons at the Fermi level, resulting in an enhancement in free O 2 capture and bonding. Meanwhile, the active center of FeN 4 is well preserved with Zn-N as the sacrificial bond during the ORR. Fe/Zn-N-C therefore achieved remarkable ORR activities in both acidic and alkaline media as well as impressive long-term durability that outperform most state-of-the-art catalysts and commercial benchmarks. This work advances our fundamental knowledge of the structure-performance relationship for ORR electrocatalysts, which could potentially inspire the exploration of high-performance candidates via electronic structure modulation. By elaborately constructing a Fe-Zn based diatomic catalyst, the active center is changed from FeN 4- ZnN 4 to FeN 4- Zn-N 2 after protonation, leading to the well-maintained FeN 4 structure and thus high stability of ORR.