NiFe layered-double-hydroxide nanosheet arrays grown in situ on Ni foam for efficient oxygen evolution reaction.

Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts under various alkaline conditions is crucial for commercial hydrogen (H₂) production. This study synthesized superhydrophilic NiFe LDH/NF with a nanosheet structure. The strong electronic interactions between the metals modify the electronic structures of Ni and Fe. In-situ Raman spectroscopy reveals numerous high-valent nickel intermediates with high OER activity during the reaction, significantly improving the catalyst's overall performance. At room temperature, the NiFe LDH/NF catalyst exhibits a current density of 50/100 mA cm−2 with only 217/233 mV required in 1 M KOH. Moreover, the catalyst requires only 180 mV under industrial conditions (60 °C, 6 M KOH), 243 mV in alkaline artificial seawater, and 280 mV in alkaline natural seawater to achieve 100 mA cm−2. The catalyst also exhibits long-term operational durability under these conditions, indicating a wide range of potential applications. [Display omitted] • NiFe LDH was directly grown in situ on a nickel foam surface by a hydrothermal method. • The catalyst's nanosheet structure and superhydrophilicity enhance the exposure of active sites to the electrolyte. • The two metalssynergistically alter the electronic structure,generating numerous high-valent active metals. • The catalysts demonstrate high activity and stability in alkaline media, even under harsh industrial conditions and seawater. [ABSTRACT FROM AUTHOR]