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.

中文翻译：

---

酸性析氧反应条件下超薄单晶 IrO2(110) 薄膜的操作稳定性研究

在酸性水分解过程中，通过独特的操作技术组合研究了负载在体积稍微减小的 TiO ₂ (110) 单晶上的 50 Å 厚单晶 IrO ₂ (110) 膜的阳极腐蚀行为，即基于同步加速器的高- 能量 X 射线反射率 (XRR) 和表面 X 射线衍射 (SXRD) 以及高灵敏度电感耦合等离子体质谱 (ICP-MS)。IrO ₂ (110) 模型电极的腐蚀引起的结构和形态变化可以通过原位 XRR 和 SXRD 在原子尺度上进行跟踪，并辅以非原位扫描隧道显微镜 (STM) 和 X 射线光电子能谱 (XPS)，而使用 ICP-MS，腐蚀速率可以量化低至 1 pg·cm ^–2·s ^–1时间分辨率为第二个刻度。基于操作同步加速器的 X 射线散射技术对大约26 小时内约 0.10 个 IrO ₂ (110)单层的 Ir 腐蚀非常敏感，即 0.4 pg·cm ^-2 ·s ^-1。本研究表明，单晶 IrO ₂(110) 薄膜比迄今为止预期的要稳定得多。尽管溶出率非常小，但 ICP-MS 实验显示出比操作高能 XRR/SXRD 实验显着更高的溶出率。这些溶解速率的差异被认为是由于 ICP-MS（动态）和操作 XRR/SXRD 实验（稳态）中遇到的不同操作模式，当氢气生产与间歇能量耦合时可能需要考虑这一事实可再生能源等来源。