Decorating ZIF-67-derived cobalt–nitrogen doped carbon nanocapsules on 3D carbon frameworks for efficient oxygen reduction and oxygen evolution

The rational construct of bifunctional electrocatalysts with high active and excellent cycling durability is the top priority for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Recently, metal-nitrogen-doped carbon (M-N-C) components formed by transition metal (TM) combined with nitrogen-doped carbon materials have drawn extensive interests due to their inexpensive cost and great activity. Herein, a straightforward evaporation-pyrolysis strategy is designed for the preparation of 3D hierarchical electrocatalyst (abbreviated as [email protected]–[email protected], which represented carbonization products at 900 °C) made of nitrogen-doped hollow carbon nanocapsules combined with Co nanoparticles bridged N-doped graphene by carbonization of a pristine ZIF-67/GO, enables hierarchical porous structure, high surface area (618.12 m2 g-1) and a hollow capsule-like nanostructure. Of these, the [email protected]–[email protected] composite displays outstanding electrocatalytic performances for OER (overpotential of 298 mV @ 10 mA cm-2) and ORR (0.86 V @ E1/2) in alkaline electrolyte, which could rival the most of reported materials. The tactics presented in this research may provide a powerful platform to engineer non-precious highly electroactive catalysts with a well-excogitated structure and preferable activity for clean energy conversion technologies.