High performance NiAlMo cathode with dual-mode porous structure by plasma spraying for alkaline water electrolysis hydrogen production

Alkaline water electrolysis (AWE) for highly efficient hydrogen production requires a highly active cathode. In this work, the porous NiAlMo electrodes were prepared by plasma spraying of NiAlMo and Al powders with a dual-channel powder feeding strategy. The bilayer-structured electrode consisting of a NiAlMo bond coat and a NiAlMo-Al composite coating on the top was designed. Al particles in the composite coating were used as pore former. The effect of Al powder feeding off-set distance on the molten state of Al was examined for optimizing the pore structure. The activated NiAlMo-40Al/NiAlMo electrode exhibited an apparent porosity of 36.8% and a surface roughness of Ra 12.18 μm, with an overpotential of 34.22 mV at 10 mA cm⁻² and a Tafel slope of 27.71 mV dec⁻¹, which was much lower than that of traditional NiAlMo electrodes. After a CP test for 10 h, the electrode remained intact and showed a stable overpotential of -0.34 V.