Coordination-environment regulation of atomic Co-Mn dual-sites for efficient oxygen reduction reaction

Precisely designing atomic metal-nitrogen-carbon (M-N-C) catalysts with asymmetric diatomic configurations and studying their structure–activity relationships for oxygen reduction reaction (ORR) are important for zinc-air batteries (ZABs). Herein, a dual-atomic-site catalyst (DASC) with CoN₃S-MnN₂S₂ configuration was prepared for the cathodes of ZABs. Compared with Co-N-C (Mn-free) and CoMn-N-C (S-free doping), CoMn-N/S-C exhibits excellent half-wave potential (0.883 V) and turnover frequency (1.54 e·s⁻¹·site⁻¹), surpassing most of the reported state-of-the-art Pt-free ORR catalysts. The CoMn-N/S-C-based ZABs achieve extremely high specific capacity (959 mAh·g⁻¹) and good stability (350 h@5 mA·cm⁻²). Density functional theory (DFT) calculation shows that the introduction of Mn and S can break the electron configuration symmetry of the original Co 3d orbital, lower the d-band center of the Co site, and optimize the desorption behavior of ^⋆OH intermediate, thereby increasing the ORR activity.