An efficient dual-metal single-atom catalyst for bifunctional catalysis in zinc-air batteries

Single-atom catalysts have been extensively studied due to the high atom utilization efficiency. However, the atomically dispersed dual-metal-site material for bifunctional catalysis in zinc-air battery is still rare. Herein, taking advantage of the trapping ability of graphene oxide to anchor metal ions, a dual-metal-site bifunctional catalyst with atomically dispersed FeN4 and NiN4 in the nitrogen doped graphene (Fe/Ni(1:3)-NG) is developed. Benefiting from the synergy effect between Fe and Ni, the catalytic performance can be greatly enhanced. The resultant catalyst exhibits highly efficient bifunctional catalytic activity, with the half-wave potential of 0.842 V for oxygen reduction reaction (ORR) and an overpotential of 480 mV at the current of 10 mA cm-2 for oxygen evolution reaction (OER). On the basis of bifunctional catalytic activities, the Fe/Ni(1:3)-NG based zinc-air battery shows an excellent power density (164.1 mW cm-2), outstanding specific capacity (824.3 mAh g-1) along with the prominent durability.