Facile preparation and properties of high nitrogen-containing Fe/Co/N co-doped three-dimensional graphene bifunctional oxygen catalysts for zinc air battery

Fe/Co/N co-doped multi-channel interpenetrating three-dimensional graphene catalyst (FeCo–N-3D-HG) with good oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic performances is prepared by a facile method, using poly (2,5-benzimidazole) (ABPBI), iron salt, cobalt salt and nanometer CaCO3 (template). ABPBI forms a complex with iron and cobalt ions and the complex is coated on the surface of CaCO3. The pyrolysis process is carried out in an Ar gas protection, the template is removed by acid to obtain FeCo–N-3D-HG. The results show that FeCo–N-3D-HG is three-dimensional multi-layered graphene structure with multi-channels. The catalytic performance of ORR (E1/2 = 0.860 V vs RHE) is better than 20 wt% Pt/C in O2 saturated 0.1 M KOH electrolyte. The catalyst also shows similar OER performance with the RuO2 in 1 M KOH solution. The prepared zinc-air battery exhibits outstanding peak power density (261.7 mW cm−2), preeminent specific capacity (760.1 mAh g−1), and good cycle durability (150 h).