Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for hydrogen evolution

In this work, we study the influences of current density on surface morphology and electrochemical characterization of electrodeposited Ni-Mo. The Ni-Mo composite coatings are deposited on pretreated copper substrates by electrolytic deposition. The Ni-Mo solution is taken from nickel sulfate fluid and ammonium heptamolybdate with 10 g/l. The Ni-Mo composite coatings are deposited at a temperature of 303 K with an applied current density of j dep= 10 A/dm2-30 A/dm2.We find that the corrosion resistance is improved by incorporating Mo particles into Ni matrix in 0.6-M Na Cl solution. From the potentiodynamic polarization curve of electrodeposited Ni-Mo it is confirmed that the corrosion resistance decreases with increasing applied current density. The x-ray diffraction（XRD） analyses of Ni-Mo coatings indicate three phases of Mo Ni4, Mo1.24Ni0.76, and Ni3 Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy（SEM） tests indicate that Ni-Mo coatings present cracks and pores.