Raney-nickel cathodes from Al - Mo - Ni precursor alloys for alkaline water electrolysis

Three different Ni - Al - Mo alloys (68 to 75 at.% Al, 2 to 10 at.% Mo) were used to investigate the influence of Mo on Rancey-Ni cathodes using metallography, X-ray diffraction and electron probe microanalysis as well as the electrochemical determination of the electrode potentials. The as-cast alloys were gas atomized and the powders were used to prepare layers of Ni - Al - Mo on Ni sheets by vacuum-plasma spraying. Leaching of Al out of the Al-rich phases Ni2Al3 and NiAl3 in a solution of 25 wt.% KOH left a nanocrystalline Ni layer of high porosity and surface area (> 60 m2/g) with outstanding catalytic activity. The influence of the Mo content on the catalytic activity and lifetime of these electrodes was investigated when employed as cathodes for hydrogen production.