In-situ synthesis of hierarchical NiFe-LDH/NiO nanoflowers on nickel foam as bifunctional catalyst for overall water splitting

The morphology of electrocatalysts play essential roles on water splitting. Herein, Nickel Iron Layered Double Hydroxide (NiFe-LDH)/NiO nanoflowers with hierarchical structure were successfully constructed via an in-situ oxidation and hydrothermal growth method. The assembled hierarchical structure exhibited impressive performance as a bifunctional catalyst for electrocatalysis water splitting, with low overpotentials of 196 mV (@ 10 mA cm- 2) and 1.64 V (@ 10 mA cm- 2) for OER and overall water splitting, respectively. Specifically, the hierarchical structure exposed large electrochemically active surface area, providing sufficient active sites for water splitting, and exhibited super hydrophilicity, boosting its contact with electrolytes and the desorption of evolved gas. In addition, the tight interfacial combination among Ni foam substrate, NiO, and NiFe-LDH could reduce the charge transfer resistance to only 6.54 Omega. This work offers a new strategy for designing highperformance Ni-based layered double hydroxide hierarchical structure.