In situ atomically dispersed Fe doped metal-organic framework on reduced graphene oxide as bifunctional electrocatalyst for Zn–air batteries

Abstract

It is an urgent and pressing demand to replace the traditional noble metal catalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) of Zn–air batteries. The non-precious metal catalysts exhibit a great promise for high electrocatalytic activity. Herein, we develop a simple strategy to prepare a porous atomically dispersed Fe doped ZIF-8-derived nanocatalyst supported on reduced graphene oxide (rGO). The optimal Fe–N–C/2rGO catalyst with a sandwich-like structure is constructed by a uniform Fe-doped ZIF-8 carbon particle layer covering the rGO surface, which demonstrates an excellent performance for ORR with a half-wave potential E_1/2 of 0.88 V vs. RHE and OER with a voltage of 1.56 V at 10 mA cm⁻², compared with that of commercial Pt/C (E_1/2 = 0.86 V) and IrO₂ (1.62 V at 10 mA cm⁻²) in 0.1 M KOH, respectively. The ingenious construction prevents the Fe-doped ZIF-8 particles and rGO from the agglomeration. It enables a rechargeable Zn–air battery with a high peak power density of 164 mW cm⁻² and excellent cycling stability. This approach provides a convenient path for constructing and designing highly active catalysts for the Zn–air batteries.