▎ 摘　　要

A new catalyst, cobalt carbonitride (CoCN) nanoparticles supported on nitrogen-doped graphenes (NG), was synthesized via a high temperature ammonia nitridation method. The catalyst has a core-shell structure with a highly active CoCN core and a protective cobalt oxide shell. Linear sweep voltammetry measurements show that the catalyst presents excellent activity in an oxygen reduction reaction compared to cobalt oxide supported on NG and commercial Pt/C catalysts, benefiting from the strong synergistic effect between CoCN and NG and the electronic modification of cobalt oxide by CoCN from within.