Operando Stability Studies of Ultrathin Single-Crystalline IrO2(110) Films under Acidic Oxygen Evolution Reaction Conditions

Tim Weber, Vedran Vonk, Daniel Escalera-López, Giuseppe Abbondanza, Alfred Larsson, Volkmar Koller, Marcel J.S. Abb, Zoltan Hegedüs, Thomas Bäcker, Ulrich Lienert, Gary S. Harlow, Andreas Stierle, Serhiy Cherevko, Edvin Lundgren, Herbert Over

Research output: Contribution to journalArticlepeer-review


The anodic corrosion behavior of 50 Å thick single-crystalline IrO2(110) films supported on slightly bulk-reduced TiO2(110) single crystals is studied during acidic water splitting by a unique combination of operando techniques, namely, synchrotron-based high-energy X-ray reflectivity (XRR) and surface X-ray diffraction (SXRD) together with highly sensitive inductively coupled plasma mass spectrometry (ICP-MS). Corrosion-induced structural and morphological changes of the IrO2(110) model electrode can be followed on the atomic scale by operando XRR and SXRD that are supplemented with ex situ scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), whereas with ICP-MS, the corrosion rate can be quantified down to 1 pg·cm-2·s-1 with a time resolution on the second scale. The operando synchrotron-based X-ray scattering techniques are surprisingly sensitive to Ir corrosion of about 0.10 monolayer of IrO2(110) in ∼26 h, i.e., 0.4 pg·cm-2·s-1. The present study demonstrates that single-crystalline IrO2(110) films are much more stable than hitherto expected. Although the dissolution rate is very small, ICP-MS experiments reveal a significantly higher dissolution rate than the operando high-energy XRR/SXRD experiments. These differences in dissolution rate are suggested to be due to the different modi operandi encountered in ICP-MS (dynamic) and operando XRR/SXRD experiments (steady state), a fact that may need to be considered when hydrogen production is coupled to intermittent energy sources such as renewables.

Original languageEnglish
Pages (from-to)12651-12660
Number of pages10
JournalACS Catalysis
Issue number20
Publication statusPublished - 2021 Oct 15

Subject classification (UKÄ)

  • Physical Chemistry

Free keywords

  • electrocatalyst stability
  • IrO
  • operando studies
  • oxygen evolution reaction (OER)
  • single-crystalline model electrodes
  • XRR


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