Electrocatalytic activation of Ni for H2 evolution by spontaneous deposition of Ru

Ni was activated by spontaneous deposition of Ru carried out in solutions of HCl containing RuCl3. 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 H2 evolution in 1 mol dm−3 KOH. Experiments were performed by varying temperature, HCl as well as RuCl3 concentration. The criticity of the presence of O2 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 H2 evolution from a 120 mV for bare Ni to ca. 40 mV.