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In Situ Synchrotron-Based Studies of IrO2(110)-TiO2(110) under Harsh Acidic Water Splitting Conditions : Anodic Stability and Radiation Damages

Weber, Tim ; Vonk, Vedran ; Abb, Marcel J.S. ; Evertsson, Jonas LU ; Stierle, Andreas ; Lundgren, Edvin LU and Over, Herbert (2022) In Journal of Physical Chemistry C 126(48). p.20243-20250
Abstract

In situ stability studies of an IrO2(110)-TiO2(110) model electrode are carried out under acidic water electrolysis conditions, employing synchrotron-based techniques including surface X-ray diffraction (SXRD) and X-ray reflectometry (XRR) with a photon energy of 21.5 keV. These experiments are complemented by ex situ scanning electron microscopy (SEM), scanning tunneling microscopy (STM), and X-ray photoelectron spectroscopy (XPS) experiments. Even at an anodic current density of 250 mA·cm-2during electrochemical water splitting, the IrO2(110)-TiO2(110) model electrode turned out to be stable against Ir dissolution. However, radiation-induced damages of the IrO2(110)... (More)

In situ stability studies of an IrO2(110)-TiO2(110) model electrode are carried out under acidic water electrolysis conditions, employing synchrotron-based techniques including surface X-ray diffraction (SXRD) and X-ray reflectometry (XRR) with a photon energy of 21.5 keV. These experiments are complemented by ex situ scanning electron microscopy (SEM), scanning tunneling microscopy (STM), and X-ray photoelectron spectroscopy (XPS) experiments. Even at an anodic current density of 250 mA·cm-2during electrochemical water splitting, the IrO2(110)-TiO2(110) model electrode turned out to be stable against Ir dissolution. However, radiation-induced damages of the IrO2(110) film are observed: Part of the IrO2(110) film delaminates upon heavy exposure to the synchrotron beam, while subsequently the uncovered TiO2(110) is subject to further (photon-induced) corrosion. We propose that the X-ray photons induce oxygen vacancy formation by displacing O2-ions of TiO2from regular to interstitial sites, while the potential drop across the TiO2(110) substrate leads to a migration of interstitial O2-ions from interface toward bulk TiO2. This reduction step at the interface between IrO2(110) and TiO2(110) weakens the adhesion of the epitaxially grown IrO2(110) film to the TiO2(110) substrate so that the strained IrO2(110) film is partially delaminated. Higher X-ray photon energies of 60-90 keV mitigate this degradation process.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry C
volume
126
issue
48
pages
8 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85143418654
ISSN
1932-7447
DOI
10.1021/acs.jpcc.2c06429
language
English
LU publication?
yes
id
babf90f2-79fd-4872-b8ff-1531e1683f91
date added to LUP
2023-01-30 12:36:00
date last changed
2023-12-01 05:22:26
@article{babf90f2-79fd-4872-b8ff-1531e1683f91,
  abstract     = {{<p>In situ stability studies of an IrO<sub>2</sub>(110)-TiO<sub>2</sub>(110) model electrode are carried out under acidic water electrolysis conditions, employing synchrotron-based techniques including surface X-ray diffraction (SXRD) and X-ray reflectometry (XRR) with a photon energy of 21.5 keV. These experiments are complemented by ex situ scanning electron microscopy (SEM), scanning tunneling microscopy (STM), and X-ray photoelectron spectroscopy (XPS) experiments. Even at an anodic current density of 250 mA·cm<sup>-2</sup>during electrochemical water splitting, the IrO<sub>2</sub>(110)-TiO<sub>2</sub>(110) model electrode turned out to be stable against Ir dissolution. However, radiation-induced damages of the IrO<sub>2</sub>(110) film are observed: Part of the IrO<sub>2</sub>(110) film delaminates upon heavy exposure to the synchrotron beam, while subsequently the uncovered TiO<sub>2</sub>(110) is subject to further (photon-induced) corrosion. We propose that the X-ray photons induce oxygen vacancy formation by displacing O<sup>2-</sup>ions of TiO<sub>2</sub>from regular to interstitial sites, while the potential drop across the TiO<sub>2</sub>(110) substrate leads to a migration of interstitial O<sup>2-</sup>ions from interface toward bulk TiO<sub>2</sub>. This reduction step at the interface between IrO<sub>2</sub>(110) and TiO<sub>2</sub>(110) weakens the adhesion of the epitaxially grown IrO<sub>2</sub>(110) film to the TiO<sub>2</sub>(110) substrate so that the strained IrO<sub>2</sub>(110) film is partially delaminated. Higher X-ray photon energies of 60-90 keV mitigate this degradation process.</p>}},
  author       = {{Weber, Tim and Vonk, Vedran and Abb, Marcel J.S. and Evertsson, Jonas and Stierle, Andreas and Lundgren, Edvin and Over, Herbert}},
  issn         = {{1932-7447}},
  language     = {{eng}},
  number       = {{48}},
  pages        = {{20243--20250}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry C}},
  title        = {{In Situ Synchrotron-Based Studies of IrO<sub>2</sub>(110)-TiO<sub>2</sub>(110) under Harsh Acidic Water Splitting Conditions : Anodic Stability and Radiation Damages}},
  url          = {{http://dx.doi.org/10.1021/acs.jpcc.2c06429}},
  doi          = {{10.1021/acs.jpcc.2c06429}},
  volume       = {{126}},
  year         = {{2022}},
}