Hierarchically porous aggregates of Co-N-C nanoparticles for oxygen electrocatalysis.

Herein, a novel assembled Co-N-C (A-Co-N-C) material was reported for the first time by pyrolyzing zeolitic imidazolate framework-67 (ZIF-67) nanoparticle aggregates caused by the introduction of surfactant polystyrene sulfonic acid (PSS). The A-Co-N-C has a large surface area of 455 m 2 g -1 with micropores (101 m 2 g -1 ) and mesopores (354 m 2 g -1 ). The A-Co-N-C exhibits good bifunctional catalytic oxygen reduction/evolution reaction (ORR/OER) and Zn-air battery activity. This work provides a simple but efficient strategy for constructing hierarchically porous aggregates of Co-N-C nanoparticles.