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

## TL;DR

A new dual-atom catalyst with asymmetric N2O4 coordination improves oxygen reduction reaction performance and durability.

## Contribution

An asymmetric N2O4 coordination strategy is introduced to enhance dual-atom catalysts for the oxygen reduction reaction.

## Key findings

- The MnMn-ON/C catalyst achieves a high half-wave potential of 0.925 V.
- It maintains stability for 1000 hours in a zinc–air battery with minimal performance loss.
- The strategy is transferable to other transition metals like Co, Cu, and Ni.

## 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 E1/2 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.

MnMn-ON/C dual-atom catalyst via electrospinning with an oxygenated polydentate ligand. Features: asymmetric N2O4 pocket, oxygen donors improving ORR and durability, transferable to Co/Cu/Ni.