The effect of hydrogen treatment of lead surface on its electrochemical behavior

The effect of the hydrogen treatment of a Pb/PbSO₄ electrode on the electrochemical behavior of a film of lead sulfate in a 2M H₂SO₄ solution is studied using the method of galvanostatic cycling. After the treatment, a lead sulfate film with a high resistance of ΔE/i ≈ 80 Ohm cm2 is found to appear on the lead surface. The increased resistance of the film can be attributed to the complete consumption of the hydrogen ions in the cathode reaction; it significantly decreases due to the ions’ diffusion from the solution. During the cycling (the first pulse is the hydrogen treatment, the second is the anodic formation of PbSO₄), the state of the surface of the electrode is not stabilized; it is rather modified according to the irregular periodic law. The nature of the change depends on the value of the potential, which switches the anodic pulse, as well as on the mode of the hydrogen treatment. The relaxation process of the currentless electrode potential after the hydrogen treatment shows the dynamics of the film growth with an abrupt increase in its resistance during the crystallization of a supersaturated solution in the pores.