title: In situ observation of surface species on iridium oxide nanoparticles during the oxygen evolution reaction.
abstract: 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.
authors.affiliation: Joint Center for Artificial Photosynthesis (JCAP) Energy Innovation Hub, LBNL, 1 Cyclotron Road, MS 976-JCAP, Berkeley, CA 94720 (USA).
authors.forename: Hernan G
authors.initials: HG
authors.lastname: Sanchez Casalongue
authors.forename: May Ling
authors.initials: ML
authors.lastname: Ng
authors.forename: Sarp
authors.initials: S
authors.lastname: Kaya
authors.forename: Daniel
authors.initials: D
authors.lastname: Friebel
authors.forename: Hirohito
authors.initials: H
authors.lastname: Ogasawara
authors.forename: Anders
authors.initials: A
authors.lastname: Nilsson
keywords: X-ray photoelectron spectroscopy; electrochemistry; heterogeneous catalysis; iridium oxide; oxygen evolution reaction