Zeolitic imidazolite framework derived bifunctional N,P-codoped hollow carbon sphere electrocatalysts decorated with Co2P/Fe for rechargeable Zn–air batteries

Abstract

Highly effective catalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are imperative in renewable technologies. The structural design of multifunctional electrocatalysts remains a huge challenge. Herein, a synthesis approach for hierarchical electrocatalysts is explored for embedding Co₂P nanoparticles and Fe–N_x species on hollow porous carbon spheres (Co₂P/Fe/NP–HCSs) by the pyrolysis of polystyrene@ZnCo-ZIF (PS@ZnCo-ZIF) composite precursors with the addition of PA and ferrocene. The combination of active species and hollow carbon structures endows Co₂P/Fe/NP–HCS electrocatalysts with prominent catalytic abilities for the ORR/OER. Co₂P/Fe/NP–HCSs show a positive half-wave potential (0.872 V) for the ORR while achieving a low overpotential (341 mV@10 mA cm⁻²) for the OER. Consequently, a Co₂P/Fe/NP–HCS-based Zn–air battery delivers high power density and desirable durability. This study provides a distinct synthetic strategy for preparing practical catalysts for energy conversion equipment.