Hydrangea-like sulfide NiFe layered double hydroxides grown on an undulate nickel framework as bifunctional electrocatalysts for overall water splitting

Developing efficient and low-priced catalysts with predominant durableness for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is an extraordinary challenge in the preparation of green hydrogen energy by electrochemical water splitting. Thence, we report a ponderable and accomplished method to fabricate active bifunctional electrocatalysts, in which hydrangea-like NiFe LDH sulfide nanosheets are supported on a hill-like nickel framework (NiFe LDH-Ni-S/NF). This optimal NiFe LDH-Ni-S/NF electrode exhibits excellent electrochemical properties in an alkaline medium, which requires 256 mV to fulfill a current density of 100 mA/cm 2 for the OER and 94 mV to reach 10 mA/cm 2 for the HER. An electrochemical water splitting appliance uses this bifunctional electrocatalyst as both anode and cathode, exhibiting a small cell potential (1.56 V@10 mA/cm 2 ). Besides, the water electrolyzer can suffer a long time of 20 h at 10 mA/cm 2 , showing the feasibility in a practical unbiased alkaline water splitting system. Hydrangea-like NiFe LDH sulfide nanosheets were supported on a kind of hill-like nickel framework (NiFe LDH-Ni-S/NF) for efficient overall water splitting. • A hydrangea-like nanostructure provides large surface areas and plentiful exposed edges. • The layer structure ensures sufficient contact area between electrolyte and catalyst. • The appropriate interlayer spacing facilitates the release of a gasiform product. • Overall water splitting can achieve 10 mA/cm 2 at only 1.56 V.