The oxygen electrode reaction in acid solutions on RuO 2 electrodes prepared by the thermal decomposition method

Abstract

A thermal decomposition method was employed to produce RuO 2 electrodes on titanium from RuCl 3 paste at annealing temperatures ranging from 300 to 500°C. The roughness factors of the electrodes were estimated utilizing cycling voltammetry. The electrocatalytic activities for oxygen evolution on these oxides in 1 M H 2SO 4 were determined by carrying out steady state potentiostatic measurements. The roughness factors are very high and show a sharp decrease at higher annealing temperatures. Dual Tafel slopes were found for low overpotentials of 31 mV decade -1 (low annealing temperatures) to 41 mV decade -1 (high annealing temperatures). The exchange current density remains almost constant at annealing temperatures of 350°C upwards and the overpotential is reduced with decreasing annealing temperature. The time variation of overpotential for oxygen evolution shows that the RuO 2 electrodes prepared at low annealing temperatures electrocatalytically are as stable as the best ruthenium-based oxides with iridium and/or tantalum that have been used up to now, although their catalytic durability is low at these annealing temperatures.