Surface properties of RuO2 + IrO2 mixed oxide electrodes

Abstract

The surface properties of RuO2 + IrO2 mixed oxide layers deposited on Ti by thermal decomposition of the corresponding chlorides in aqueous solutions have been investigated by means of cyclic voltammetry and ex situ UHV (AES and XPS) techniques. The data obtained have shown that the surface is enriched with Ir and also that the bulk composition is likely to be inhomogenous. The surface composition estimated on the basis of the voltammetric curves has been found to agree excellently with the results of ex situ surface analysis. Finally, the samples have been found to "absorb" protons from the solution through a mechanism which does not interfere with the estimation of the electrochemically active surface area on the basis of the voltammetric charge.