---
_id: '63675'
abstract:
- lang: eng
  text: Cobalt spinel (Co3O4) catalysts are widely studied in scope of the electrocatalytic
    oxygen evolution reaction (OER), yet the role of interfacial structural transformation
    under anodic bias remains under debate. Here, we employ an operando approach,
    combining a fast electrochemical quartz crystal microbalance with dissipation
    monitoring (EQCM-D), electrochemical impedance spectroscopy (EIS), and Raman spectroscopy
    to investigate interfacial transformations of Co3O4 nanoparticle electrodes in
    alkaline electrolyte. We identify two distinct regimes during the anodic sweep
    prior to the macroscopic OER onset. At lower potentials, the catalyst interface
    remains mechanically rigid while reversibly associating several OH−/H2O species
    per oxidized cobalt site. At higher potentials, pronounced softening of the interface
    occurs alongside further uptake of electrolyte species. This indicates amorphization
    and a ‘swelling process’ beyond simple adsorption. Notably, an electrochemical
    conditioning treatment can suppress mass and compliance hysteresis without affecting
    OER activity, suggesting that most incorporated electrolyte species do not participate
    in the OER. EIS further reveals that OER intermediates form well below the apparent
    OER onset potential. These results advance our mechanistic understanding of interfacial
    transformations in cobalt-based OER catalysts and establish EQCM-D as a sensitive
    operando technique for probing electrocatalyst transformations.
article_number: e01104
author:
- first_name: Christian
  full_name: Leppin, Christian
  id: '117722'
  last_name: Leppin
- first_name: Carsten
  full_name: Placke‐Yan, Carsten
  last_name: Placke‐Yan
- first_name: Georg
  full_name: Bendt, Georg
  last_name: Bendt
- first_name: Sheila
  full_name: Hernandez, Sheila
  last_name: Hernandez
- first_name: Kristina
  full_name: Tschulik, Kristina
  last_name: Tschulik
- first_name: Stephan
  full_name: Schulz, Stephan
  last_name: Schulz
- first_name: Julia
  full_name: Linnemann, Julia
  id: '116779'
  last_name: Linnemann
  orcid: 0000-0001-6883-5424
citation:
  ama: 'Leppin C, Placke‐Yan C, Bendt G, et al. Interfacial Softening and Electrolyte
    Uptake in Co<sub>3</sub>O<sub>4</sub> OER Catalysts: Insight from <i>Operando</i>
    Spectroscopy and Fast EQCM‐D. <i>ChemCatChem</i>. 2026;18(2). doi:<a href="https://doi.org/10.1002/cctc.202501104">10.1002/cctc.202501104</a>'
  apa: 'Leppin, C., Placke‐Yan, C., Bendt, G., Hernandez, S., Tschulik, K., Schulz,
    S., &#38; Linnemann, J. (2026). Interfacial Softening and Electrolyte Uptake in
    Co<sub>3</sub>O<sub>4</sub> OER Catalysts: Insight from <i>Operando</i> Spectroscopy
    and Fast EQCM‐D. <i>ChemCatChem</i>, <i>18</i>(2), Article e01104. <a href="https://doi.org/10.1002/cctc.202501104">https://doi.org/10.1002/cctc.202501104</a>'
  bibtex: '@article{Leppin_Placke‐Yan_Bendt_Hernandez_Tschulik_Schulz_Linnemann_2026,
    title={Interfacial Softening and Electrolyte Uptake in Co<sub>3</sub>O<sub>4</sub>
    OER Catalysts: Insight from <i>Operando</i> Spectroscopy and Fast EQCM‐D}, volume={18},
    DOI={<a href="https://doi.org/10.1002/cctc.202501104">10.1002/cctc.202501104</a>},
    number={2e01104}, journal={ChemCatChem}, publisher={Wiley}, author={Leppin, Christian
    and Placke‐Yan, Carsten and Bendt, Georg and Hernandez, Sheila and Tschulik, Kristina
    and Schulz, Stephan and Linnemann, Julia}, year={2026} }'
  chicago: 'Leppin, Christian, Carsten Placke‐Yan, Georg Bendt, Sheila Hernandez,
    Kristina Tschulik, Stephan Schulz, and Julia Linnemann. “Interfacial Softening
    and Electrolyte Uptake in Co<sub>3</sub>O<sub>4</sub> OER Catalysts: Insight from
    <i>Operando</i> Spectroscopy and Fast EQCM‐D.” <i>ChemCatChem</i> 18, no. 2 (2026).
    <a href="https://doi.org/10.1002/cctc.202501104">https://doi.org/10.1002/cctc.202501104</a>.'
  ieee: 'C. Leppin <i>et al.</i>, “Interfacial Softening and Electrolyte Uptake in
    Co<sub>3</sub>O<sub>4</sub> OER Catalysts: Insight from <i>Operando</i> Spectroscopy
    and Fast EQCM‐D,” <i>ChemCatChem</i>, vol. 18, no. 2, Art. no. e01104, 2026, doi:
    <a href="https://doi.org/10.1002/cctc.202501104">10.1002/cctc.202501104</a>.'
  mla: 'Leppin, Christian, et al. “Interfacial Softening and Electrolyte Uptake in
    Co<sub>3</sub>O<sub>4</sub> OER Catalysts: Insight from <i>Operando</i> Spectroscopy
    and Fast EQCM‐D.” <i>ChemCatChem</i>, vol. 18, no. 2, e01104, Wiley, 2026, doi:<a
    href="https://doi.org/10.1002/cctc.202501104">10.1002/cctc.202501104</a>.'
  short: C. Leppin, C. Placke‐Yan, G. Bendt, S. Hernandez, K. Tschulik, S. Schulz,
    J. Linnemann, ChemCatChem 18 (2026).
date_created: 2026-01-20T19:33:40Z
date_updated: 2026-01-20T19:36:51Z
department:
- _id: '985'
doi: 10.1002/cctc.202501104
intvolume: '        18'
issue: '2'
keyword:
- electrocatalysis
- Co3O4
- EQCM-D
- OER
language:
- iso: eng
main_file_link:
- open_access: '1'
oa: '1'
publication: ChemCatChem
publication_identifier:
  issn:
  - 1867-3880
  - 1867-3899
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: 'Interfacial Softening and Electrolyte Uptake in Co<sub>3</sub>O<sub>4</sub>
  OER Catalysts: Insight from <i>Operando</i> Spectroscopy and Fast EQCM‐D'
type: journal_article
user_id: '116779'
volume: 18
year: '2026'
...