Investigation of the oxygen evolution reaction on Ti/IrO2 electrodes using isotope labelling and on-line mass spectrometry

Autor: Helmut Baltruschat, Stéphane Fierro, Christos Comninellis, Tina Nagel
Rok vydání: 2007
Předmět:
Zdroj: Electrochemistry Communications, Vol 9, Iss 8, Pp 1969-1974 (2007)
ISSN: 1388-2481
DOI: 10.1016/j.elecom.2007.05.008
Popis: Oxygen evolution on Ti/IrO2 anodes has been studied in 1M HClO4 electrolyte using 18O labelling together with differential electrochemical mass spectrometry (DEMS) measurements.It has been shown that during successive cyclic voltammetric measurements in H2 18O containing electrolyte the amount of 16O2 (m/z = 32) decreases, with a concomitant increase of 18O16O (m/z = 34) after each cycle before reaching a steady state after four cycles. The obtained higher 16O2 concentration in the evolved oxygen during the first scans is because 16O from the IrO2 film contribute in the oxygen evolution reaction.Analysis of the experimental data has shown that the amount of lattice oxygen, which is involved in the oxygen exchange reaction, is in the order of 1% of the total IrO2 loading. This is an indication that only the outer surface of the oxide electrode participates in the oxygen evolution reaction.In a second series of experiments it has been demonstrated that oxygen evolution on Ir16O2 in H218O containing electrolyte result in the formation of Ir18O2.Consequently, we can conclude that the IrO2 layers participate in the oxygen evolution reaction in acid media at least to a several monolayer extend. Keywords: Oxygen evolution, Metal oxide electrodes, IrO2, Isotope labelling, DEMS
Databáze: OpenAIRE
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