Corrosion-engineered NiMnFe(OH)_x@NiMn/TP core–shell electrode for anion exchange membrane water electrolyzers

Exploring cost-effective and highly efficient electrodes is crucial for realizing future renewable energy systems for anion exchange membrane water electrolyzers (AEMWE). There are two half-reactions that occur during water electrolysis, and the development of an effective electrode for the sluggish oxygen evolution reaction (OER) is considered as a key aspect of the half-reaction. In this study, a ternary metal hydroxides electrode was fabricated using a two-step (electrodeposition and corrosion engineering) process. The hydrogen bubble templating electrodeposition enabled the control of the morphology from a dense film to a porous coral-like electrode. Furthermore, Fe was introduced to the electrode to form a core–shell structure via corrosion engineering. The OER catalytic activities of the electrodes were compared in a half-cell, and the results indicated that the optimized electrode required values of 322 mV at 50 mA cm⁻². Additionally, stability test was conducted at 100 mA cm⁻² for 12 h, and the results indicated that the variation ratio was observed at 1.90 mV h⁻¹. The optimized NiMnFe(OH)_x@NiMn/TP was utilized into a membrane electrode assembly (MEA) as an anode, and the catalytic activity of the anode was tested in a single-cell of AEMWE, and it exhibited a current density of 1.5 A cm⁻² at 2.02 V_cell and maintained its performance for more than 50 h.