Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka, Japan
Abstract:
Electrochemical properties of ruthenium, particularly the anodic evolution of oxygen and anodic dissolution of ruthenium have been investigated by means of polarization measurements and product analyses. The electrode surface gradually colours black during oxygen evolution. This is due to the accumulation of hydrous RuO2 resulting from decomposition of corrosion product. The black oxide film suppresses the ruthenium dissolution rate and the current efficiency for the dissolution reaction is less than 6% at a cd below 0.2 A/cm2 in 1 N H2SO4, where the anodic evolution of oxygen is predominant. The overall current for oxygen evolution is expressed by i = nFka?2H exp (2FE/RT) The probable mechanism of oxygen evolution on the ruthenium anode under the Langmuir conditions of intermediate adsorption is
