Promoting interfacial charge transfer by B/N co-doping enables efficient ORR catalysis of carbon-encapsulated Fe2N

B/N co-doping carbon shell encapsulated Fe 2 N nanoparticles to catalyze ORR. Pyridinic-N and C–N–B sites are active sites to facilitate electron traverse from the Fe 2 N to the carbon shell, and tailor the electronic properties of the carbon layer towards high ORR activity.