Boosting the electrocatalytic activity and stability of Ni/NiO toward the oxygen evolution reaction by coupling FeOOH nanosheets.

The unsatisfactory performance of the oxygen evolution reaction (OER) and the complex preparation methods are the main challenges hindering the industrial application of OER electrocatalysts in electrochemical water splitting for hydrogen production. Herein, a convenient two-step method including electrodeposition and subsequent chemical bath deposition was utilized to synthesize a FeOOH/Ni/NiO tri-component composite on Ti mesh (TM), during which Ni(Ac)₂ and FeSO₄ were used as feedstocks. XRD, Raman, XPS, SEM and TEM characterizations revealed nanosheet-assembled nanospheres composed of crystalline Ni coated by amorphous NiO, and amorphous FeOOH nanosheets successively deposited on the TM surface by electrodeposition and chemical bath deposition strategies. When serving as the OER electrocatalyst, the optimized FeOOH/Ni/NiO/TM presented a superb OER performance with an overpotential of 246 mV at 50 mA cm⁻², outperforming FeOOH-5/NF (321 mV), Ni/NiO/TM (348 mV) and the recently reported electrocatalysts. Additionally, its OER performance had no obvious change with only 4.3% attenuation after working for 16 h at a constant current density. The high OER performance could be assigned to the interfacial electronic engineering due to the strong coupling effect between FeOOH and Ni/NO, which increased the intrinsic activity of the active sites, modulated the adsorption of the reactant and also enhanced the stability. The simple preparation strategy, low cost and high performance endow the self-supporting FeOOH/Ni/NiO/TM with potential applications in industrial water electrolysis for hydrogen production. [ABSTRACT FROM AUTHOR]