Electrochemical and morphological properties of Ti/Ru0.3 Pb(0.7-x) TixO2-coated electrodes

In this work, a ternary coating with the nominal composition Ti/Ru0.3Pb(0.7-x)TixO2 (0 less than or equal to x less than or equal to 0.7) deposited on Ti has been prepared through thermal decomposition of ruthenium, titanium and lead inorganic salts dissolved in isopropanol. To find out coatings with reasonable service life for application in electrolysis devices, changes in the firing temperature, heating time and supporting electrolyte have been investigated. Surface morphology and microstructure have been investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). SEM data show that the mud-crack structure is progressively lost with the substitution of titanium by lead oxides. EDS results suggest that lead segregates, forming islands with a high content of Pb. Changes in crystallinity have been obtained with an increase in the lead content. Electrochemical analyses have been carried out in acid medium (HClO4 1.0 mol dm(-3) and H2SO4 0.5 mol dm(-3)). Cyclic voltammetric data and quasi-steady-state polarization curves have been recorded and accelerated life tests have been performed with an anodic current of 400 mA cm(-2). High coating stability has been obtained with the electrode fired at 550degreesC. Replacing Ti with Pb extends the service life and improves the catalytic activity for oxygen evolution reaction (OER). (C) 2003 Elsevier Ltd. All rights reserved.