Coupling of NiFe-Based Metal-Organic Framework Nanosheet Arrays with Embedded Fe-Ni3S2 Clusters as Efficient Bifunctional Electrocatalysts for Overall Water Splitting

Developing highly efficient,easy-to-make and cost-effective bifunc-tional electrocatalysts for water splitting with lower cell voltages is crucial to produc-ing massive hydrogen fuel.In response,the coupled hierarchical Ni/Fe-based MOF nanosheet arrays with embedded metal sulfide nanoclusters onto nickel foam skele-ton(denoted as Fe-Ni3S2@NiFe-MOF/NF)are fabricated,in which the Fe-Ni3S2 clus-ters could effectively restrain the aggregation of the layer metal-organic frameworks(MOF)nanosheets and adjust the local electronic structures of MOFs nanosheets.Benefiting from the rapid charge transfer and the exposure of abundant active sites,the well-designed Fe-Ni3S2@NiFe-MOF/NF displays excellent oxygen evolution re-action(OER)and hydrogen evolution reaction(HER)performance.More importantly,when equipped in the alkaline water electrolyzer,the Fe-Ni3S2@NiFe-MOF/NF ena-bles the system with a mere 1.6 V for achieving the current density of 10 mA cm-2.This work offers a paradigm for designing efficient bifunctional HER/OER electrocatalysts based on the hybrid materials of nanostructured metal sulfide and MOF.