CoFe Alloys Dispersed on Se, N Co-Doped Graphitic Carbon as Efficient Bifunctional Catalysts for Zn-Air Batteries

The development of a stable and efficient non-noble metal catalyst with both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is paramount to achieving the widespread application of Zn-air batteries (ZABs) but remains a great challenge. Herein, a novel Co3Fe7 alloy nanoparticle dispersed on Se, N co-doped graphitic carbon (denoted as CoFe/Se@CN) was prepared through a facile hydrothermal and pyrolysis process. The synthesized CoFe/Se@CN exhibits outstanding ORR and OER properties with an ultralow potential gap of 0.625 V, which is mainly attributed to the abundant porous structure, the rich structural defects formed by doping Se atoms, and the strong synergistic effects between the CoFe alloys and graphitic carbon nanosheet. Furthermore, the ZAB fabricated by CoFe/Se@CN shows a high peak power density of 160 mW cm-2 and a large specific capacity of 802 mA h g-1 with favorable cycling stability, outperforming that of Pt/C+RuO2. Our study offers a plausible strategy to explore bifunctional carbon-based materials with efficient electrocatalytic properties for rechargeable ZABs. CoFe/Se@CN with abundant porous structure was obtained through a self-sacrificing template method. The large specific surface area and the mesopores of CoFe/Se@CN provide rich active sites and facilitate the transport and transfer of protons and electrons. The abundant defects formed by doping Se enhance the oxygen adsorption/activation of carbon surfaces and increase active sites. Under the synergistic effect of CoFe alloys and Se, N co-doped graphitic carbon, CoFe/Se@CN exhibits excellent ORR and OER properties with an ultralow potential gap of 0.625 V.image