SYNERGETIC EFFECT OF ELECTRODE ACTIVATION ON THE HER IN ALKALINE-MEDIUM ON PT, PD, NI AND CU ELECTRODES

Platinum, palladium, nickel and copper surfaces were modified from acid baths containing SiW12O404- and different concentrations of Cu2+. It was shown that improvement in the overpotential (eta) and in the exchange current density (i0) of the hydrogen evolution reaction (h.e.r.) on the electrodes, in alkaline medium, depends on the concentration of Cu2+. The copper concentration displaying the best electrocatalytic behaviour for the h.e.r. was determined for the different electrodes. The h.e.r. electrocatalytic activity was then analysed and related to the chemical composition of their surface deposits. The performance of the modified electrodes was also checked through potentiostatic experiments. This showed that the improvement in the electrocatalytic properties was attributable, not to an increase in the surface area of the electrode, but to the chemical composition of the surface deposits.