Fully Synthetic Approach toward Transition Metal–Nitrogen–Carbon Oxygen Reduction Electrocatalysts

We report a nonpyrolytic chemical synthesis of model iron–nitrogen–carbon electrocatalysts for oxygen reduction reaction (ORR) to elucidate the role of Fe–N centers in the catalysis mechanism. The graphene-supported and unsupported catalysts were analyzed in detail by X-ray spectroscopy techniques. The electrochemical analysis was performed by linear sweep voltammetry and square wave voltammetry in 0.5 M H2SO4 and 0.1 M KOH electrolytes. In this article, with the use of model catalysts, we manifest and confirm the difference in the specific role of Fe–N active sites toward ORR in acidic and alkaline environments.