First-principles Study of the Catalytic Mechanism of Fe-doped Co-N-C Cathode in Lithium-air Batteries
Metal-organic frameworks (MOFs) derived porous nitrogen-doped carbon materials loaded with cobalt single-atom cata-lysts (Co-N-C) have emerged as promising oxygen electrochemical catalysts due to their high stability and good durability.Howev-er,they generally exhibit insufficient bifunctional pathway catalytic activity and high selectivity for hydrogen peroxide because of limited improvements in the adsorption capabilities for oxygen intermediates.Herein,based on doping engineering,a Fe-doped Co-N-C structure (Fe@Co-N-C) is constructed using single-atom doping to enhance the adsorption of intermediates.Based on first-prin-ciples calculations,the changes in crystal size and density of states before and after Fe doping are analyzed.The results show that after Fe doping,the bond length of Co-N decreases and the interaction becomes stronger.From the total density of states perspective,near the Fermi level,Fe@Co-N-C material exhibits a higher density of states compared to Co-N-C.As for the partial density of states,the d-band center of the Co atom in Fe@Co-N-C material is closer to the Fermi level compared to that in Co-N-C mate-rial,indicating a lower electron transfer barrier and enhanced catalytic activity.
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