Tuning the atomic configuration environment of MnN4 sites by Co cooperation for efficient oxygen reduction

Carbon-based N-coordinated Mn (Mn-Nx/C) single-atom electrocatalysts are considered as one of the most desirable non-precious oxygen reduction reaction (ORR) candidates due to their insignificant Fenton reactivity, high abundance, and intriguing electrocatalytic performance. However, current Mn-Nx/C single-atom electrocatalysts suffer from high overpotentials because of their low intrinsic activity and unsatisfactory chemical stability. Herein, through an in-situ polymerization-assisted pyrolysis, the Co as a second metal is introduced into the Mn-Nx/C system to construct Co, Mn-Nx dual-metallic sites, which atomically disperse in N-doped 1D carbon nanorods, denoted as Co, Mn-N/CNR and hereafter. Using electron microscopy and X-ray absorption spectroscopy (XAS) techniques, we verify the uniform dispersion of CoN4 and MnN4 atomic sites and confirm the effect of Co doping on the MnN4 electronic structure. Density functional theory (DFT) calculations further elucidate that the energy barrier of rate-determining step (*OH desorption) decreases over the 2 N-bridged MnCoN6 moieties related to the pure MnN4. This work provides an effective strategy to modulate the local coordination environment and electronic structure of MnN4 active sites for improving their ORR activity and stability.