A Facile Topochemical Preparation of Ni-Fe LDH Nanosheets Array on Nickel Foam Using In Situ Generated Ni2+ for Electrochemical Oxygen Evolution

Herein, we presented a simple one-step method to prepare Ni-Fe layer double hydroxide nanosheets array (Ni-Fe LDH NSA) integrated electrodes under anaerobic condition at room temperature using untreated nickel foam (NF) as substrate and the NiO thin layer thereon as the Ni2+ source. FeSO4 is utilized as Fe source. The amorphous NiO layer on NF can be dissolved in the weak acidic Fe2+ solution. NH4HCO3 is added to adjust the pH value for controlled hydrolysis of Ni2+ and Fe2+ became brucite to LDH after exposed on the air. Fe-O-Fe and Ni-O-Fe moieties can be lead in during this facile topochemical preparation of Ni-Fe LDH. The structure of electrodes was characterized by SEM, TEM, XPS, XRD, etc. The OER performance of the integrated electrode was tested by a series of electrochemical measurement. The prepared integrated electrode Ni-Fe LDH/NF shows good OER performance with relatively low overpotential (198 mV at 10 mA cm−2), moderate tafel slope (70 mV dec−1) and high electrochemical stability.