Fe&Fe₂O₃ Dual-Decorated on N-Doped Porous Carbon for Oxygen Reduction Reaction

Abstract

Catalysts for the cathodic oxygen reduction reaction (ORR) are important in fuel cells. Herein, a class of non-precious metal ORR catalyst, namely Fe&Fe 2 O 3 dual-decorated on N-doped porous carbon (Fe&Fe 2 O 3 /NC), is prepared from the pyrolysis of a mixture containing Fe 2 O 3 /NC, Fe salt and melamine, followed by acid-leaching, where Fe 2 O 3 /NC is firstly synthesized from one-step pyrolyzing the precursors of coal, KOH, melamine and Fe salt. As a result, the Fe&Fe 2 O 3 /NC provides a much better ORR catalytic activity with the peak potential (E p ) and half-wave potential (E 1/2 ) of 902 mV and 852 mV, respectively, than these of Fe 2 O 3 /NC (824 mV and 768 mV) and close to these of 20 wt% commercial Pt/C (918 mV and 863 mV). Furthermore, the ORR occurred on Fe&Fe 2 O 3 /NC follows near a four-electron transfer pathway. It also has a good stability and methanol-resistance. By comparing the structures of Fe 2 O 3 /NC and Fe&Fe 2 O 3 /NC, the essential roles on improving the ORR catalytic activity are discussed: both the abundant graphitic N active sites and the synergistic effect of Fe and Fe 2 O 3 play important roles. This work not only provides a general guideline for the design and development of non-precious metal-based catalysts for ORR but also enriches the application scope of coal.