Material and organic destruction characteristics of high temperature-sintered RuO2 and IrO2 electrodes

For Ru and Ir oxide electrodes sintered at different temperatures, in this work, surface resistivity, X-ray photoelectron spectroscopy, electrode lifetime, voltammetric charge capacity, and total organic carbon of 4-chlorophenol (4CP) decomposition at the electrodes were measured, and then intermediates during the electrolysis were identified by gas chromatography-mass spectroscopy to predict the destruction path of 4CP at the electrodes. A sintering temperature of around 650degreesC, rather than 400-550degreesC suggested in the literature for the fabrication of Ru and Ir oxide electrode, showed the highest organic destruction yield. The sintering temperature strongly affected the electrode lifetime as well. During the high temperature sintering, increase of the sintering time caused the oxidation of the Ti substrate to result in the increase of oxide weight of the electrode and the solid diffusion of the generated TiO2 to the electrode surface, which decreased the electrode activity so that the organic destruction yield went down slowly. The destruction path of 4CP at a high temperature-sintered electrode was suggested to be different from that at a low temperature-sintered one. The Ru oxide electrode sintered at 450degreesC generated several complicated aliphatic intermediates. (C) 2002 The Electrochemical Society.