Hydrogen evolution on the polyethylene-modified Ni-Mo composite layers

The Ni-Mo + PENi layers were prepared by electrodeposition from a bath containing a suspension of polyethylene subjected to preliminary nickel plating (PENi). Surface morphology was examined using scanning electron microscope. The potentiodynamic and electrochemical impedance spectroscopy methods were used for characterisation of electrochemical activity during hydrogen evolution. Based on the obtained results parameters of hydrogen evolution process have been determined. It was found that the process proceeds better on the layers containing the embedded PENi than on the Ni-Mo layers. Kinetic parameters of hydrogen evolution are better for the Ni-Mo + PE layers than for comparable Ni-Mo alloy. It was concluded that embedding the polymer into the layer results in local shielding of the electrode surface and directing the electrochemical process to the free areas thus improving kinetics of hydrogen evolution process. (C) 2007 Elsevier B.V. All rights reserved.