Post incorporation of Fe sites on defective carbon sponge with high accessibility to enhance oxygen reduction elecrocatalysis

Monodispersed Fe-N/C single-atom catalysts have excellent oxygen reduction reaction (ORR) activity in renewable energy applications. Improving the availability and stability of iron monatomic catalytic sites is challenging. Herein, an iron phthalocyanine (FePc)-based vapor deposition strategy was designed for the synthesis of monodispersed Fe-N/C single-atom catalysts. The construction of Fe-N sites with both stability and high activity on defection-rich carbon surface has been realized, ascribed to the well balance between the evaporation and decomposition of FePc on defective carbon sponge (DCS) to generate enough Fe-N active sites with full accessibility. As a result, the optimized catalyst delivered excellent ORR activity, selectivity and stability, as well promising zinc-air battery performance with good power density and discharging stability. Our results cast new insight into rational construction of easily accessible and highly active Fe-N sites. [Display omitted] •An FePc-based vapor deposition strategy was proposed to construct highly active and accessible Fe-Nx sites.•The balance between the evaporation and decomposition of FePc generated high-density Fe-Nx active sites.•Potential application of the developed FePc@DCS catalysts in zinc-air battery was demonstrated.