Iron Carbide Nanoparticles Embedded in Edge-Rich, N and F Codoped Graphene/Carbon Nanotubes Hybrid for Oxygen Electrocatalysis.

Rational design of cost-effective and efficient bifunctional oxygen electrocatalysts for sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is urgently desired for rechargeable metal–air batteries and regenerative fuel cells. Here, the Fe3C nanoparticles encapsulated in N and F codoped and simultaneously etched graphene/CNTs architecture catalyst (Fe3C@N-F-GCNTs) was synthesized by a simple yet cost-effective strategy. The as-prepared Fe3C@N-F-GCNTs exhibited excellent ORR and OER performances, with the ORR half-wave potential positive than that of Pt/C by 14 mV, and the OER overpotential lowered to 432 mV at the current density of 10 mA·cm−2. In addition, the ΔE value (oxygen electrode activity parameter) increased to 0.827 V, which is comparable to the performance of the best nonprecious metal catalysts reported to date. When it was applied in a Zn–air battery as a cathode, it achieved a peak power density of 130 mW·cm−2, exhibiting the potential for large-scale applications. [ABSTRACT FROM AUTHOR]