Axial Coordination Modulation of FeN4 Sites in Dioxin-Linked Covalent Organic Hybrid Catalysts for Enhanced ORR Activity and Zinc–Air Battery Application

Effective regulation of the adsorption strength of oxygen reduction reaction (ORR) intermediates on active sites is the key to enhancing their catalytic performance. This study proposes an axial coordination modulation strategy by successfully anchoring the dioxin-linked FePcF16-based covalent organic frameworks (COFs) onto amino-functionalized multi-walled carbon nanotubes (NH2-MWCNTs), constructing a FePcF16-COF/NH2-MWCNT hybrid catalyst. Experimental results demonstrate that the catalyst exhibits outstanding ORR activity (E1/2= 0.901 V; JL= 5.133 mA cm−2), outperforming commercial 20% Pt/C and most reported Fe-based non-precious metal catalysts. Furthermore, the robust dioxin-linked COF skeleton endows the catalyst with excellent electrochemical stability. A zinc–air battery using this catalyst as the cathode also demonstrates superior power density and cycling performance. This work provides a new strategy for designing highly efficient ORR catalysts through axial coordination environment engineering.