In situ observation of surface species on iridium oxide nanoparticles during the oxygen evolution reaction

Angew Chem Int Ed Engl. 2014 Jul 7;53(28):7169-72. doi: 10.1002/anie.201402311. Epub 2014 May 28.


An iridium oxide nanoparticle electrocatalyst under oxygen evolution reaction conditions was probed in situ by ambient-pressure X-ray photoelectron spectroscopy. Under OER conditions, iridium undergoes a change in oxidation state from Ir(IV) to Ir(V) that takes place predominantly at the surface of the catalyst. The chemical change in iridium is coupled to a decrease in surface hydroxide, providing experimental evidence which strongly suggests that the oxygen evolution reaction on iridium oxide occurs through an OOH-mediated deprotonation mechanism.

Keywords: X-ray photoelectron spectroscopy; electrochemistry; heterogeneous catalysis; iridium oxide; oxygen evolution reaction.