Nanostructured NiCo2S4@NiCo2O4-reduced graphene oxide as an efficient hydrogen evolution electrocatalyst in alkaline electrolyte

Metal-organic frameworks (MOFs), serving as precursors or templated to construct nanomaterials , which have gained great attentions in the field of electrocatalysis . However, their applications still remain some challenges due to poor conductivity and easy agglomeration. In this work, the MOFs-derived NiCo 2 S 4 @NiCo 2 O 4 deposited on reduced Graphene Oxide (rGO) surface is designed by using a facile hydrothermal procedure. Attribute to the enlarged active surface area of the nanostructure and the strong synergistic effect between NiCo 2 S 4 and NiCo 2 O 4 , as well as the excellent conductivity of rGO. The NiCo 2 S 4 @NiCo 2 O 4 -rGO catalyst displays ultrahigh hydrogen evolution reaction (HER) property and excellent stability, only need an overpotential of η 10  = 95 mV to attain 10 mA cm −2 and deliver a small Tafel slope of b  = 52 mV dec −1 in 1 M KOH. This work can provide a window to construct and develop new noble metal-free HER catalysts base on Ni-MOFs served as precursors.