THE ELECTROCHEMICAL R.EDUCTION OF OXYGEN ON PASSIVE IRON

CALVO, E.J.; SCHIFFRIN, DJ

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

Elsevier

Lugar: Amsterdam; Año: 1988 vol. 243 p. 171 - 185

0022-0728

The reduction of oxygen on passive iron in alkaline solutions has been studied. The reaction orders with respect to 0s and OH- are f and - 1 respectively. The proposed reduction mechanism involves the mediation of surface [Fe@)] sites formed by reduction of the passive film which act as adsorption centres. It is suggested that the formation of adsorbed peroxo species under Temkin conditions accounts for the 0, reaction order whereas the acid-base properties of the passive films are responsible for the OH- reaction order. At potentials around -0.4 to -0.5 V vs. SHE, an unusual decrease in current with increasing rotation rate is observed, which is related to the desorption of adsorbed peroxide.