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 Ti3C2 MXene-decorated nickel foam (Ti3C2 MXene/NF) by hydrothermal reaction (NiFeS@Ti3C2 MXene/NF). The morphology of NiFeS and in-teractions with Ti3C2 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@Ti3C2 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||RuO2 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 degrees 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.

Automated summary

In this study, NiFeS@Ti3C2 MXene/NF catalyst with excellent water splitting performance in an alkaline membrane water electrolyzer was prepared. It features low catalyst loading and low operating temperature, which will contribute to commercial green hydrogen production.