Synergistic Fe,Pd diatomic sites anchored on porous nitrogen-doped carbon for efficient oxygen reduction in the entire pH range

Abstract

Diatomic catalysts (DACs) have shown great potential for the oxygen reduction reaction (ORR). However, designing highly active and durable DACs that perform efficiently across the entire pH range remains a significant challenge. In this work, we introduce a novel Fe,Pd diatomic catalyst (Fe,Pd–NC), in which Pd serves as an effective electronic modulator adjacent to Fe, supported on a porous nitrogen-doped carbon matrix. By optimizing the electronic environment and enhancing the accessibility of Fe,Pd diatomic sites, Fe,Pd–NC demonstrates outstanding ORR activity across all pH conditions, achieving half-wave potentials of 0.884 V, 0.782 V, and 0.781 V in alkaline, neutral, and acidic media, respectively. Furthermore, Fe,Pd–NC exhibits exceptional durability across the pH spectrum. When incorporated into zinc–air batteries (ZABs) operating in alkaline and neutral electrolytes, the Fe,Pd–NC catalyst delivers superior power density, specific capacity, and long-term stability, outperforming conventional Pt/C-based ZABs. This study presents an effective design strategy for DACs with universal pH adaptability, offering promising applications in energy conversion and storage devices.