Anodic oxidation of lead indium alloys in sulphate solution. The electrocatalysis of the anodic oxygen transfer reaction.

In order to enhance the electrocatalytic activity of the lead dioxide towar ds the anodic oxygen transfer reaction, the anodic oxide layer formed in th e lead dioxide potential region was modified by alloying lead with indium. First, XRD and SEM analyses have shown a weak influence of the indium on th e structure and the morphology of the modified anodic oxide layer, suggesti ng that the doping element is introduced in the PbO2 lattice by the substit ution of Pb+IV by In+III ion. Secondly, the oxygen evolution reaction (OER) was studied in neutral sulpha te solution in terms of oxygen overvoltage and Tafel plot measurements. The influence of the indium content in the PbO2 layer towards the electrocatal ysis of the anodic oxygen transfer reaction during the oxidation of DMSO ch osen as model molecule was outlined. The enhancement of the anodic O-transf er reaction with the increase of the indium content is confirmed by the res ults of the phenol electrochemical oxidation. The improvement of the electr ocatalytic effect can be ascribed to a better interaction between the activ e oxygen surface sites and the adsorbed organic molecules.