Cobalt nanoclusters promoted coordination-field enhancement of manganese single atoms for robust alkaline oxygen reduction reaction.

Bimetallic component catalysts, especially those with heteronucleation active sites, have recently attracted significant attention due to multi-component synergism and fast electron transfers. Herein, we report an architecture of dual-metal Mn/Co components loaded catalyst (MnCo-20) derived from metal-organic frameworks (MOFs) through simple wet-chemical synthesis followed by pyrolysis. By using various advanced characterization techniques, we confirm that Co exists in the form of nanoclusters and Mn exists as single atoms on the nitrogen-doped carbon support. Compared with single-metal counterparts, our MnCo-20 shows significantly higher electrocatalytic performance in the oxygen reduction reaction (ORR), with a half-wave potential as high as 0.912 V, even superior to the commercial Pt/C catalyst. X-ray absorption spectroscopy experiments and density functional theory (DFT) calculations indicate that the MnN site mainly acts as the functional unit. As the Co nanoclusters tune the coordination field of the Mn active site by changing the charge distribution, their synergy significantly accelerates ORR kinetics. DFT calculations demonstrate that Co nanoclusters effectively lower the d-band center of Mn sites, thereby optimizing the adsorption and desorption energies of key oxygen intermediates (*OOH, *O, *OH). Such precise modulation reduces the Gibbs free energy barriers associated with ORR steps, facilitating a highly efficient four-electron transfer pathway under alkaline conditions. It opens up a new path for the design of high-performance, low-cost ORR catalysts and also provides a new insight into the ORR mechanism.