Salt template synthesis of CoO@Co nanoparticles encapsulated in 3D porous nitrogen‐doped carbon for oxygen reduction reaction

Abstract Developing high performance and cost‐effective electrocatalysts toward oxygen reduction reaction (ORR) is of critical significance for fuel cells and metal–air batteries. Herein, CoO@Co nanoparticles encapsulated in three‐dimensional (3D) porous nitrogen‐doped carbon (CoO@Co/Co‐N‐C) have been successfully derived from the cobalt–tannin framework via the NH 4 Cl salt template strategy. Owing to the generated NH 3 and HCl gas from NH 4 Cl during the pyrolysis process, CoO@Co/Co‐N‐C formed a 3D porous carbon architecture with ultrahigh‐specific surface area (1052.5 m 2 g −1 ). This hybrid catalyst exhibits comparable ORR catalytic activity, as well as superior stability to 20 wt% Pt/C in alkaline conditions. This finding offers a novel and facile strategy to synthesize 3D porous carbon as non‐precious metal electrocatalysts for energy conversion and storage applications.