A universal N2O4-cavity strategy for precisely spaced, durable dual-atom ORR catalysts

Abstract

Diatomic catalysts offer greater promise than single-atom catalysts for the oxygen reduction reaction (ORR), yet simultaneously controlling atomic spacing, maximizing performance, and suppressing degradation remains challenging in conventional M–N₄ frameworks. Here, we introduce an asymmetric N₂O₄ coordination in place of traditional N₄ symmetry and, via an oxygen-coordinated polydentate ligand-electrospinning strategy, synthesize a MnMn-ON/C diatomic catalyst. MnMn-ON/C delivers a high half-wave potential E_1/2 of 0.925 V, exceeding most reported asymmetric Mn-based diatomic catalysts. After 50 000 cycles it lost only 11 mV, and it operated stably in a zinc–air battery for 1000 hours without significant performance degradation, representing the best overall performance among asymmetric manganese-based diatomic systems. In situ spectroscopy combined with DFT reveals that N₂O₄-induced electronic coupling at Mn diatomic sites strengthens *OOH adsorption, while oxygen coordination tunes the density of states near the Fermi level. The cavity-confined architecture and strong Mn–O bonding jointly suppress migration and aggregation of active sites, enabling reversible valence regulation and recoverable activity. This asymmetric coordination-cavity strategy affords precise control of diatomic spacing and extends to other transition metals (Co, Cu, Ni), offering a general route to mitigate performance degradation in non-precious metal ORR catalysts.