Effect of the interfacial electronic coupling of nickel-iron sulfide nanosheets with layer Ti3C2 MXenes as efficient bifunctional electrocatalysts for anion-exchange membrane water electrolysis

In this study, nickel-iron sulfide (NiFeS) nanosheets were immobilized on Ti 3 C 2 MXene-decorated nickel foam (Ti 3 C 2 MXene/NF) by hydrothermal reaction (NiFeS@Ti 3 C 2 MXene/NF). The morphology of NiFeS and interactions with Ti 3 C 2 MXene resulted in electronic coupling that optimized the adsorption energies of water, protons, and oxygen atom for the HER (180 mV@20 mA cm -2 ) and OER (290 mV@20 mA cm -2 ). The NiFeS@Ti 3 C 2 MXene/NF catalyst showed good water splitting performance in an alkaline membrane water electrolyzer, yielding a current density ( j ) of 401 mA cm -2 at 1.85 V with 67.65% cell efficiency, performance comparable to Pt/C||RuO 2 cells. From a commercial point of view, our electrolyzers are the best because of their low loading of catalysts (ca. 1.25 mg cm -2 ) and low operating temperatures (50 °C), resulting in low capital and operating costs. Our findings will aid the development of commercial green hydrogen production and offers an alternative to PEMWE. We demonstrate the excellent activity and stability of an electrolyzer system based on NiFeS@Ti 3 C 2 MXene/nickel foam self-standing anodes and cathodes. • Ti 3 C 2 MXenes/NF decorated with NiFeS nanosheets to yield electrocatalyst. • Electronic coupling of NiFeS with Ti 3 C 2 MXenes promotes catalytic activity. • Current density of 20 mA cm -2 at overpotentials of 180 mV (HER) and 290 mV (OER). • Alkaline anion-exchange membrane water electrolyzer (AEMWE) tested. • AEMWE suitable for commercial production of green hydrogen.