Oxygen evolution on Ru and Ir electrodes: XPS-studies

Abstract Anodic corrosion and O 2 -evolution on Ru and Ir electrodes in 0.5 M H 2 SO 4 has been investigated using X-ray photoelectron spectroscopy. On Ru a highly defective hydrated oxide film is formed during O 2 -evolution. The relative stability of thermally treated RuO 2 electrodes is correlated to the presence of RuO 3 on the electrode surface. Oxygen evolution on Ir proceeds on a thin oxide layer which corrodes during the evolution reaction. A reaction path for O 2 -evolution and corrosion on Ru is proposed.