Study on the Simple Surface Treatments of N, P Dual‐doped Carbon as Metal‐free Catalyst for Metal‐air Batteries.

N, P dual‐doped porous carbon with high specific surface area of ∼2000 m2 g−1 was prepared via foaming‐carbonization process. It was demonstrated that the simple surface treatment and modification can conveniently further improve the catalytic performance of oxygen reduction reaction (ORR). The results showed that chemisorbed phosphorus can promote the surface treatment of sodium borohydride (NaBH4). The modified novel sites, adsorbing water molecules of a semi‐free state, promoted the offensive key steps of H2O molecules in ORR. After post‐treatment, the limit current density increased from 5.0 to 6.1 mA cm−2 with a decreased Tafel slope and the onset potential positively shifted. This surface‐modified catalyst was applied to Zn‐air battery and Al‐air battery, and had exhibited good applicability and excellent performances. This work illustrates that the simple post‐treatments can conveniently and effectively improve the ORR performance of metal‐free carbon catalysts. [ABSTRACT FROM AUTHOR]