Fully\nSynthetic Approach toward Transition Metal–Nitrogen–Carbon\nOxygen Reduction Electrocatalysts

Abstract

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