Oxygen evolution on Ru and RuO2 electrodes studied using isotope labelling and on-line mass spectrometry

Abstract Oxide layer formation and O2 evolution on Ru and RuO2 films have been studied in sulphuric acid using 18O labelling together with differential electrochemical mass spectrometry (DEMS). It was shown that 16O18O is evolved from a H216O solution on a Ru oxide layer previously formed in H218O. 16O18O was also observed when oxygen is evolved on Ru16O2 in H218O solution. Consequently, the oxide layer takes part in the oxygen evolution process on both types of electrode. In the case of Ru, formation of RuO4 was observed when oxygen evolution takes place.