Multilayer Oxide Films on Anodized Platinum

Abstract

A voltammetric study is described of conditions governing the production and stability of anodically formed bulk oxide on Pt in dilute H2SO4. The range of anodizing conditions covered in 1 or 2N H2SO4 was: current-density, up to 10 A/cm2; temperature, 11~176 duration, up to 18 hr. The oxidizabil-ity of the Pt anode (with respect to formation of bulk oxide) was subject to considerable hysteresis. Provided a potential of about 2.15V, RHE was exceeded, electrode oxidizability seemed to be controlled largely by the amount of strain energy present in the Pt surface. The electrolytic formation and reduction of thick bulk oxide layers effected large increases in electrode roughness factor (up to 100X or more). Superficial, monolayer-type oxide films on platinum electrodes which have been anodized in aqueous solu-tion are very well known although far from completely characterized. The l iterature on this type of film which