Passive Films on Iron: The Mechanism of Breakdown in Chloride Containing Solutions

Abstract

The electroreduction kinetics of surface modified were investigated. The surface was modified by electrodeposition of Co, Ru, Rh, Pt, Co/Pt, Ru/Pt, and Rh/Pt. Exchange current densities for hydrogen evolution were obtained both in the dark and under 100 mW/cm² illumination. For sequentially deposited metals, values are lower compared to individually deposited metals during hydrogen evolution. Cathodic currents observed positive of the hydrogen‐evolution region can be explained by electron‐transfer processes involving surface states. In this latter potential region, values are higher for the sequentially deposited metals.