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

摘要

In this work, we study the infl uences 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 fl uid 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 jdep=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 NaCl 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 MoNi4, Mo1.24Ni0.76, and Ni3Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy (SEM) tests indicate that Ni–Mo coatings present cracks and pores.