Polypyrrole hydrogel as a universal precursor for the target preparation of heteroatom-doped hierarchical carbon with atomically distributed metal sites towards high-efficiency ORR and Zn–air batteries

Atomically Fe anchored N,P-doped carbon was prepared via direct pyrolysis of polypyrrole hydrogel, which showed competitive ORR activity to Pt/C both in alkaline/acidic media, as well as superior application potential in Zn–air battery.