Homogeneous Coating of Al-Doped Spinel Oxides on Ni Mesh for Efficient Oxygen Evolution Reaction

Industrial alkaline water electrolysis requires a catalyst electrode with high alkaline resistance and scalability due to the high alkaline concentration, frequent gas desorption, and high hydrogen production power involved. However, most high-performance oxygen evolution reaction (OER) catalysts are poorly adhered to conductive substrates, such as nickel foam or carbon paper, leading to detachment and performance degradation under harsh industrial conditions. Here, we report a simple and scalable strategy of “immersion-infrared drying-calcination” to fabricate Al-doped spinel oxides in situ grown on mechanically robust Ni mesh. By further simple cation substitution, we effectively modulate the metal-oxygen bond length in the octahedral center and the valence state of active sites, significantly enhancing OER activity. Electrochemical tests (1 M KOH, 25°C) show that NiAl_0.5Co_1.5O₄ exhibits excellent performance with an overpotential of 234 mV at a current density of 10 mA cm⁻². Remarkably, under industrial conditions (6 M KOH, 60°C), it achieves an overpotential of only 448 mV at a current density of 400 mA cm⁻², which is superior to that of commercial Raney Ni catalysts. Moreover, the scalable electrode demonstrates excellent resistance to concentrated alkaline solutions and high current densities.