On the kinetics of the hydrogen evolution reaction on Ni-MoOx composite catalysts in alkaline solutions

MoO3 particles were co-deposited with Ni onto smooth or rough Ni supports from modified Watt baths of different compositions. Morphology and composition of the electrodeposits were characterized by means of cyclic voltammetry, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic activity of the composite catalysts for H-2 evolution in alkaline solutions was determined by quasi-stationary polarization curves. Activity increases with MoOx content in the Ni deposit up to a limiting value. The composite Ni-MoOx catalysts exhibited high catalytic activity, similar to that of a commercial Ni-RuO2 catalyst. Stability tests showed that the Ni-MoOx co-deposits were stable under constant current conditions and exhibited excellent tolerance to repeated short-circuiting.