Surface chemistry of RuO2/IrO2/TiO2 mixed-oxide electrodes: secondary ion mass spectrometric study of the changes induced by electrochemical treatment

The IrO2/RuO2/TiO2 ternary system is web known for its electrocatalytic act ivity towards oxygen- and chlorine-evolution reactions. Electrochemical pro cessing induces noticeable chemical and morphological modifications on thes e electrodes, depending on the noble metal oxide content. In this work, cat hodic/anodic polarization and the oxygen-evolution reaction were studied in order to evaluate the electrocatalytic activity at various noble metal oxi de percentages. The best performing electrode (30 mol% noble metal oxides) was analyzed before and after electrochemical tests by means of secondary i on mass spectrometry (SIR IS) in order to determine the chemical compositio n modification which occurred on the surface and in deeper regions of the m ixed-oxide film. Copyright (C) 2000 John Wiley & Sons, Ltd.