NiCoFe-layered double hydroxides/MXene/N-doped carbon nanotube composite as a high performance bifunctional catalyst for oxygen electrocatalytic reactions in metal-air batteries

It is tremendously desired to fabricate high-performance, low-cost and highly capable electrocatalysts performing oxygen electrocatalytic reactions (reduction and evolution) in rechargeable metal–air batteries. In this study, heterostructure of NiCoFe-layerd double hydroxide (LDH)/Ti3C2 (MXene)/N-doped carbon nanotube (NCNT) was constructed via a simple hydrothermal method. Thanks to the hybrid porous architecture possessing extensive surface area, high electrical conductivity, plentiful active sites, optimum nitrogen content and robust electronic interactions in the NiCoFe-LDH/Ti3C2 MXene/NCNT, the resulted composite presented superb electrocatalytic activity toward oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Specially, it showed an overpotential of 332 mV to reach J = 10 mA cm−2 for the OER and at the same time presented starting potential of Eonset = 0.93 VRHE with E1/2 = 0.78 VRHE for the ORR. In addition, utilized in a Zn-air battery, it exhibited higher power density and greater cycling capability than Pt/C-IrO2 catalyst, introducing it as a promising catalyst for rechargeable Zn-air batteries.