Coal-Derived N-Doped Porous Carbon Accompanied with Fe2O3 for Oxygen Reduction Reaction

Abstract

In this study, a class of non-precious metal catalyst for oxygen reduction reaction (ORR), namely N-doped porous carbon accompanied with Fe2O3 (herein named as AC-4), is synthesized from one-step pyrolyzing the precursors of KOH, coal, Fe salt and melamine, followed by acid-leaching. Several catalysts, AC-1 from KOH + coal, AC-2 from KOH + coal + melamine and AC-3 from KOH + coal + Fe salt, are also shown for comparison. As a result, AC-4 provides the best ORR catalytic activity with the ORR peak potential (Ep) of 818 mV, followed by the order of AC-2 (783 mV) > AC-3 (775 mV) > AC-1(771 mV), meaning that the N-doping strategy plays more effect than the Fe2O3-doping method, and AC-4 has the synergetic effect of these two ways. Furthermore, the ORR mechanism on AC-4 is near a four-electron transfer pathway with the electron transfer number around 3.7–3.9. It also has a good stability and methanol-resistance. Structure measurements display that introduction of N heteroatom and/or metal can increase the disorder degree of AC, and AC-4 has a structure of N-doped porous carbon (the special surface area of 1193 m2 g−1) accompanied with Fe2O3.