Mn-Fe dual atomic pairs on highly graphitized N-doped carbon support for oxygen reduction reaction.

Developing highly active and durable catalysts for the sluggish oxygen reduction reaction (ORR) is crucial for the widespread application of metal-air batteries. In this work, a Mn-Fe diatomic catalyst supported on N-doped carbon (Mn-Fe/NC) was synthesized via a two-step pyrolysis method. Structural characterization confirmed that the atomically dispersed Mn-Fe pair sites were anchored on a support rich in pyridinic N and graphitic N. The catalyst exhibits outstanding ORR performance in alkaline conditions, with a high half-wave potential of 0.903 V (vs. RHE), a low Tafel slope of 79.7 mV dec-1, and excellent stability (<10% decay after 15 h), outperforming commercial Pt/C and the corresponding single-metal counterparts. The enhanced activity is attributed to the synergistic electronic interaction between adjacent Mn and Fe sites. When applied as a cathode in zinc-air batteries (ZABs), Mn-Fe/NC delivers higher peak power density (80.3 mW cm-2) and specific capacity (806.1 mAh gZn -1) than Pt/C, demonstrating great potential for practical application in energy conversion devices.