Abstract:

Platinum electrodes were oxidized by means of an " undulant " current. It was found by chemical analysis that the product was practically pure PtO2. HjO ; this was deposited in the anodic, compartment (using i % sulphuric acid as electrolyte) at a rate ot 0-025 g./hr. Details of optimum conditions are given. A tentative theoretical explanation is offered which combines Ershler's theory of the passivity of platinum with the dispersion of the double layer capacity with A.c. frequency as found by Dolin and Ershler : A.c. diminishes the double layer capacity thereby increasing the potential drop to a value permitting the dissolution of the ion.