EFFECT OF COMPOSITION ON THE ELECTROCATALYTIC ACTIVITY OF THE TERNARY OXIDE RU0.3TI(0.7-X)SNXO2 .1. OXYGEN EVOLUTION FROM HCLO4 SOLUTIONS

The electrocatalytic activity of ternary oxides of general formula Ru0.3Ti(0.7−x)SnxO2 for O2 evolution from 1 mol dm−3 HClO4 solution has been studied as a function of x by current-potential curves and reaction order determination. The surface state of the electrodes has been monitored by voltammetric curves before and after each run of experiments. The mechanism of O2 evolution has been found not to depend on oxide composition, whereas the electrocatalytic activity has been observed to rise as the SnO2 content increases. The surface charge drops dramatically after extensive O2 evolution, thus indicating collapse of the surface morphology. The open-circuit potential and the shape of the voltammetric curves have also been used as diagnostic parameters. The present results show that SnO2 activates RuO2 + TiO2 electrodes, consequently decreasing their stability. © 1990, The Electrochemical Society, Inc. All rights reserved.