A carbon material doped with both porous FeOx and N as an efficient catalyst for oxygen reduction reactions

Abstract

To replace precious metal oxygen reduction reaction (ORR) electrocatalysts, many transition metals and N-doped carbon composites have been proposed in the last decade resulting in their rapid development as promising non-precious metal catalysts. We used Ketjenblack carbon as the precursor and mixed it with a polymeric ionic liquid (PIL) of [Hvim]NO₃ and Fe(NO₃)₃, which was thermally calcined at 900 °C to produce a porous FeO_x, N co-doped carbon material denoted FeO_x-N/C. Because the PIL of [Hvim]NO₃ strongly combines with and disperses Fe³⁺ ions, and NO³⁻ is thermally pyrolyzed to form the porous structure, the FeO_x-N/C catalyst has a high electrocatalytic activity for the ORR in both 0.1 mol L⁻¹ KOH and 0.5 mol L⁻¹ H₂SO₄ electrolytes. It was used as the catalyst to assemble a zinc-air battery, which had a peak power density of 185 mW·cm⁻². Its superior electrocatalytic activity, wide pH range, and easy preparation make FeO_x-N/C a promising electrocatalyst for fuel cells and metal-air batteries.