Breaking the O ₂ Activation Bottleneck via Synergistic Electronic Polarization at Adjacent Co–Mn Sites in N‐Doped Carbon

ABSTRACT

Metal‐nitrogen‐carbon (M‐N‐C) catalysts with atomically dispersed metal sites have emerged as attractive non‐precious alternatives to Pt/C for the oxygen reduction reaction (ORR). Among them, Co‐N‐C systems have received particular attention because of their favorable stability and low cost, yet isolated Co sites often exhibit insufficient O ₂ adsorption and charge polarization, limiting further activity enhancement. In this study, we introduce Mn into a Co‐N‐C matrix via a confined adsorption approach to create adjacent Co–Mn sites. The presence of adjacent Mn electronically modulates the Co center, resulting in a CoMnNC catalyst with markedly improved ORR performance. The catalyst delivers half‐wave potential ( E _1/2 ) values of 0.80 V in 0.1 M HClO ₄ and 0.919 V in 0.1 M KOH. Under Zn‐air battery testing, its maximum power density reached 193.5 mW cm ⁻² , outperforming Pt/C under identical conditions. Density functional theory (DFT) calculations indicate Mn proximity enriches the electron density at Co and downshifts the Co d‐band center. This electronic modulation enhances O ₂ adsorption and charge polarization, weakens the adsorbed O─O bond and lowers the barrier for OOH* formation. This work clarifies how neighboring metal sites regulate the electronic structure of Co centers to facilitate O ₂ activation and offers a reference for designing excellent M‐N‐C catalysts.