A one-stone-three-birds strategy to construct Mo-FeS2/Ni3S2@C electrocatalyst with strong interfacial coupling effect to achieve efficient oxygen evolution reaction

The development of high-performance oxygen evolution reaction (OER) electrocatalysts is quite pivotal to facilitate hydrogen production. In this work, we integrate the synergistic effects of heterogeneous interface engineering, multiscale engineering and doping engineering to greatly improve the catalytic activity of the electrocatalyst. Specifically, with a Anderson-type polymetallic oxonate (NH4)3[NiMo6O24H6]·7H2O as a precursor, the Mo-FeS2/Ni3S2@C nanowire arrays that uniformly grown on nickel foam (NF) surfaces were prepared by a simple hydrothermal process followed by calcination. The as-prepared Mo-FeS2/Ni3S2@C exhibits excellent alkaline OER performance with a low overpotential of 196 mV to achieve a current density of 10 mA cm−2 and maintain high stability for over 100 h at 100 mA cm−2. Theoretical calculations and experimental results indicate that the high activity of Mo-FeS2/Ni3S2@C is mainly attributed to the charge interaction at the multiple interfaces of FeS2, Ni3S2 and porous carbon layers. The Mo facilitates inducing the formation of high-valent Ni, Fe, thus forming of the Ni(Fe)OOH phase that contributes to the intrinsic OER active site of the Mo-FeS2/Ni3S2@C electrode. In addition, the surface of Mo-FeS2/Ni3S2@C nanowire is composed of ordered nanosheets, exhibiting a unique hierarchical multi-scale structure, which is conducive to exposing more active sites. This hierarchical structure gives it superhydrophilic and superoxyphobic properties, ensuring the stability during continuous electrolysis. This study showcases the importance of multi-engineering synergies and foresees the avenue of designing novel OER electrocatalysts.