Establishing structure/property relationships in atomically dispersed Co-Fe dual site M-N_xcatalysts on microporous carbon for the oxygen reduction reaction

Coupled metal-nitrogen-carbon (M-N_x-C) materials show great promise as platinum-group-metal (PGM) free catalysts for the oxygen reduction reaction (ORR). Herein, we report a facile strategy to construct atomically dispersed Co-Fe dual sites enriched on the surface of nitrogen doped microporous carbon (NC) as an efficient electrocatalyst for ORR. Synchrotron X-ray techniques indicate that the Co and Fe atoms are strongly correlated while further revealing that the longer-range lattice structure of NC is highly tunable. Density functional theory calculations reveal that the Co-Fe dimers are incorporated in the slightly disordered NC substrate, providing a lower adsorption free energy for O₂. The as-prepared CoFe-NC catalyst exhibited excellent ORR activities, while a CoFe-NC based zinc-air battery exhibited a power density of 115 mW cm⁻²and a specific capacity of 791 mA h g⁻¹. This work showcases a straightforward methodology for creating atomically dispersed catalysts and illustrates the importance of understanding how dual metal sites impact electrocatalytic activity.