EFFECT OF SOLUTION PH ON HYDROUS OXIDE-GROWTH AND REDUCTION ON POLYCRYSTALLINE PLATINUM

The study of hydrous oxides produced on platinum by the potential cycling technique is complicated by the presence, in many instances, of more than one component in such deposits. Where possible, conditions favouring the growth of single component films were employed in the present work; it was confirmed that a portion (in some cases up to 70%) of these hydrous oxide deposits was resistant to reduction in base at low potentials, e.g. 0.13 V (RHE) for 10 min; this was attributed to the anionic character of such materials. The presence of a thick hydrous oxide film on the anode surface had a slight inhibiting effect on the Kolbe reaction on platinum in aqueous acetate solution.