Anodic dissolution and electrocatalytic properties of Fe 60Co 20Si 10B 10 amorphous alloy in 1 M KOH

The anodic dissolution and the electrocatalytic properties of Fe 60Co 20Si 10B 10 (Vitrovrac 7600, G14) amorphous alloy in de-aerated 1 M KOH aqueous solutions were investigated at 25 and 70°C by different electrochemical techniques (cyclic voltammetry, cathodic polarisation, and galvanostatic transients). The results obtained show that voltammograms for the amorphous alloy change with time becoming stable after 20-25 cycles between -1900 and +100 mmV vs saturated sulphate electrode. Comparisons among voltammograms for polycrystalline iron, cobalt and the amorphous alloy, suggest that the first step of the anodic dissolution of the amorphous alloy is cobalt dissolution. The stable voltammogram of the amorphous alloy is quite similar to that of pure iron in the same environment, suggesting that after 20-25 cycles only iron dissolves. The electrocatalytic properties of the amorphous alloy vs the hydrogen evolution reaction in 1 M KOH increases by increasing the number of cycles which have been attributed to a porous Fe 3O 4 layer covering the amorphous surface. © 1994