THE HYDROGEN EVOLUTION REACTION IN AN ACID-MEDIUM ON A NICKEL COPPER ALLOY ELECTRODEPOSITED WITH HETEROPOLYACIDS

The hydrogen evolution reaction (h.e.r.) in an acid medium on nickel electrodeposited with copper and PMo12O403-, PW12O403- or MoO42- has been studied. In particular, the electrocatalytic parameters of nickel electrodeposited with 2 x 10(-3) M PMo12O403- and different concentrations of Cu2+ have been determined. The best electrocatalytic parameters have been obtained on nickel electrodeposited with 2 x 10(-3) M PMo12O403- and 2 x 10(-3) M Cu2+. Analogous results were obtained on nickel electrodeposited with 2 x 10(-3) M PW12O403- or 2 x 10(-3) M MoO42- for which the best h.e.r. parameters are obtained with electrodes fabricated with 2 x 10(-3) M Cu2+. The chemical composition of the electrodes have been correlated to their electrocatalytic parameters. The best electrodes for the h.e.r. are Ni-Mo-Cu or Ni-W-Cu alloys. The electrocatalytic parameters of Ni-Mo-Cu alloy are better than those of Ni-W-Cu. These results were attributed to the number of d-electrons of W(5d4) and Mo(4d5).