In situ electrochemical atomic force microscopy of lead electrodes in sulfuric acid solution with or without lignin during anodic oxidation and cathodic reduction

The surface morphologies of lead sheets in sulfuric acid solution, with or without lignin, under temperature control during anodic oxidation and cathodic reduction are investigated by using in situ electrochemical atomic force microscopy combined with cyclic voltammetry. Whether lignosulfonate (lignin) is added or not, it is found at −20 °C that the precipitation of lead sulfate crystals occurs immediately after supersaturation of dissolved Pb2+ ions at the anodic oxidation peak on the cyclic voltammogram. It is also observed that the density of lead sulfate crystals formed on the lead electrode after anodic oxidation decreases and the crystal size becomes larger when lignin is added. Furthermore, the addition of lignin delays dissolution of lead sulfate crystals during cathodic reduction at room temperature (RT).