Construction of δ-FeOOH/NiMn2S4 heterointerface for efficient alkaline oxygen evolution reaction

Alkaline water electrolysis driven by sustainable energy is a viable approach for large-scale green hydrogen production. The development of non-precious metal-based electrocatalysts that combine high activity and stability for the alkaline oxygen evolution reaction (OER) is of great importance. In this work, we design and construct a δ-FeOOH/NiMn 2 S 4 /NF heterointerface using a solvothermal/calcination process followed by a facile successive ionic layer adsorption reaction (SILAR) treatment. Experimental tests indicate that the formation of the heterogeneous interface between the δ-FeOOH and the NiMn 2 S 4 creates a good electron transport channel for an efficient electrocatalytic process and improves the charge transfer kinetics. As a result, the prepared δ-FeOOH/NiMn 2 S 4 /NF exhibits a low overpotential of 210 mV at 10 mA cm −2 and a low Tafel slope value of 46.6 mV dec −1 , and satisfactory stability with a 92.9 % retention after 72 h of OER operation at around 100 mA cm −2 . In situ Raman and in-situ attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) tests show that the introduction of δ-FeOOH inhibits the oxidation of Ni 2+ to Ni 3+ and stabilizes the Ni-S bond to prevent its auto-oxidation, leads to an increase in the electrocatalytic OER activity.