Highly dispersed γ-Fe2O3 embedded in nitrogen doped carbon for the efficient oxygen reduction reaction

Abstract

The development of non-precious metal electrocatalysts with both high activity and durability to replace costly Pt-based catalysts for the oxygen reduction reaction (ORR) is still a major challenge. Composites of metal-oxide(s) and nitrogen doped (N-doped) carbon have emerged as promising candidates for the ORR in energy conversion and metal–air batteries. Herein, we report a versatile and robust sacrificial template approach to synthesize highly dispersed γ-Fe₂O₃ embedded in porous N-doped carbon with a high surface area. The as-prepared Fe₂O₃@NC-800 possesses a pure phase of γ-Fe₂O₃ with a small size, which interacts synergistically with N-doped carbon to increase ORR activity and selectivity. Fe₂O₃@NC-800 performs better than the commercial 20 wt% Pt/C as well as most iron-based non-precious metal catalysts reported previously. The assembled zinc–air battery with Fe₂O₃@NC-800 as a cathode catalyst exhibits a maximum power density of 112 mW cm⁻² along with good operation durability, which is superior to that of 20 wt% Pt/C (68 mW cm⁻²).