Fe–Nx–C sites decorated porous carbon nanorods with huge specific surface area boost oxygen reduction catalysis for Zn-air batteries.

• Acid etching and NH 3 activation exposed more homodispersed Fe-N x -C active sites. • Fe-PCNRs-700 has a hierarchical porous structure and huge specific surface area. • Fe-PCNRs-700 exhibits excellent ORR activity in acidic and alkaline media. • Zn-air batteries are assembled with high power density and robust stability. Acid etching and NH 3 activation can not only increase the specific surface area of the catalyst, but also expose more Fe–N x –C active sites. Finally, the prepared Fe-PCNRs-700 exhibited excellent ORR activity and Zn-air battery performance. [Display omitted] Decorating porous carbon nanomaterials with rich homodispersed metal cluster and heteroatoms can effectively shorten the diffusion pathway of oxygen and expose more active sites, thereby promoting oxygen reduction reaction (ORR). Herein, hierarchical porous carbon nanorods with homodispersed Fe–N x –C active sites are obtained by calcination, etching and ammonia activation of Fe-nitrogenous acid (NTA) coordination polymer nanowires. The obtained Fe-PCNRs-700 as ORR catalysts show the excellent activity with half wave potential (E 1/2) of 0.71 V vs. reversible hydrogen electrode (RHE) in 0.5 M H 2 SO 4 and 0.87 V vs. RHE in 0.1 M KOH electrolyte, which owe to its huge specific surface area (1652 m2 g−1), hierarchical pore structure, homodispersed Fe–N x –C active sites and structural defects. Furthermore, using Fe-PCNRs-700 as a cathode catalyst in both liquid and flexible solid Zn-air batteries, and the assembled liquid batteries display the high power density of 161 mW cm−2 and robust charge/discharge stability of 116 h. [ABSTRACT FROM AUTHOR]