Post iron-doping of activated nitrogen-doped carbon spheres as a high-activity oxygen reduction electrocatalyst

Post-doping of Fe into activated N-doped carbon nanospheres obtains very high activity for the oxygen reduction reaction superior and comparable to those of precious Pt/C in both alkaline and acidic electrolytes, ascribed to the synergy of hierarchical micro-/mesopores, improved surface area/porosity and Fe-Nx coordinated active sites.267