Designed synthesis of cobalt nanoparticles embedded carbon nanocages as bifunctional electrocatalysts for oxygen evolution and reduction

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are fundamental for many renewable energy conversion and storage technologies. Developing economic and durable bifunctional ORR and OER electrocatalysts as substitute for noble-metal based catalysts, are urgently expected to reduce the industrial cost. Herein, a strategy towards synthesizing cobalt nanoparticles embedded N-doped carbon hollow nanocages (Co@NPC-H) by ion exchanging is reported. The Co@NPC-H nanocage structures integrate the high activity of heteroatoms doped catalytic active sites with the hollow structure for high exposure ratio of the active sites, exhibiting superior electroctalytic performance to noble-metal catalyst for both ORR and OER with the application potential of 860 mV when used as bifunctional catalyst, much smaller than other reported electrocatalysts, making Co@NPC-H a promising candidate as efficient air electrode in Zn-air batteries. (C) 2018 Published by Elsevier Ltd.