Ni was activated by spontaneous deposition of Ru carried out in solutions of HCl containing RuCl 3 . The occurrence of Ru deposition was confirmed by EDX and XPS and followed as a function of deposition time by cyclic voltammetry and Tafel lines for H 2 evolution in 1moldm −3 KOH. Experiments were performed by varying temperature, HCl as well as RuCl 3 concentration. The criticity of the presence of O 2 in solution was demonstrated. Ni activation by Ru is manifested by the appearance of H adsorption peaks in the voltammetric curve, and by the decrease of the Tafel slope for H 2 evolution from a 120mV for bare Ni to ca. 40mV.