---
_id: '62813'
abstract:
- lang: eng
  text: Nanostructured manganese oxides have a rich variety of morphologies and crystal
    phases which can undergo transformations during synthesis and application. Although
    these structural features are crucial for their performance, the mechanisms behind
    such transitions are not well understood. Herein, we describe the mechanism of
    transformation from layered 2D δ-MnO2 nanosheets to the scarcely reported γ-MnO2
    nanocone morphology. Despite the common purpose of introducing Fe dopants to enhance
    the conductivity of layered manganese oxides, the Fe galvanic exchange reaction
    was found responsible for such coupled phase/morphology transition. Electrochemical
    characterization confirmed a distinct electrochemical behaviour of the nanocones,
    emphasizing the need to unravel the mechanism of 2D MnO2 transformation. Such
    mechanistic insights were gained by systematic and rigorous electron microscopy
    studies. The effect of the local chemical composition was determined by energy
    dispersive X-ray spectroscopy while electron energy loss spectroscopy unravelled
    the key influence of the oxidation state of Mn ions within nanosheets and nanocones.
    We propose and demonstrate a Mn2+-mediated oxidative mechanism of coupled morphology/phase
    transformation subjected to the equilibrium of Fe and Mn ions during galvanic
    exchange reaction. These findings contribute to the understanding of the growth
    and morphology/phase transformations of manganese oxide nanostructures, providing
    insights for the rational design of nanomaterials.
article_type: original
author:
- first_name: Raquel
  full_name: Aymerich-Armengol, Raquel
  last_name: Aymerich-Armengol
- first_name: Paolo
  full_name: Cignoni, Paolo
  last_name: Cignoni
- first_name: Petra
  full_name: Ebbinghaus, Petra
  last_name: Ebbinghaus
- first_name: Julia
  full_name: Linnemann, Julia
  id: '116779'
  last_name: Linnemann
  orcid: 0000-0001-6883-5424
- first_name: Martin
  full_name: Rabe, Martin
  last_name: Rabe
- first_name: Kristina
  full_name: Tschulik, Kristina
  last_name: Tschulik
- first_name: Christina
  full_name: Scheu, Christina
  last_name: Scheu
- first_name: Joohyun
  full_name: Lim, Joohyun
  last_name: Lim
citation:
  ama: Aymerich-Armengol R, Cignoni P, Ebbinghaus P, et al. Mechanism of coupled phase/morphology
    transformation of 2D manganese oxides through Fe galvanic exchange reaction. <i>Journal
    of Materials Chemistry A</i>. 2022;10(45):24190-24198. doi:<a href="https://doi.org/10.1039/d2ta06552e">10.1039/d2ta06552e</a>
  apa: Aymerich-Armengol, R., Cignoni, P., Ebbinghaus, P., Linnemann, J., Rabe, M.,
    Tschulik, K., Scheu, C., &#38; Lim, J. (2022). Mechanism of coupled phase/morphology
    transformation of 2D manganese oxides through Fe galvanic exchange reaction. <i>Journal
    of Materials Chemistry A</i>, <i>10</i>(45), 24190–24198. <a href="https://doi.org/10.1039/d2ta06552e">https://doi.org/10.1039/d2ta06552e</a>
  bibtex: '@article{Aymerich-Armengol_Cignoni_Ebbinghaus_Linnemann_Rabe_Tschulik_Scheu_Lim_2022,
    title={Mechanism of coupled phase/morphology transformation of 2D manganese oxides
    through Fe galvanic exchange reaction}, volume={10}, DOI={<a href="https://doi.org/10.1039/d2ta06552e">10.1039/d2ta06552e</a>},
    number={45}, journal={Journal of Materials Chemistry A}, publisher={Royal Society
    of Chemistry (RSC)}, author={Aymerich-Armengol, Raquel and Cignoni, Paolo and
    Ebbinghaus, Petra and Linnemann, Julia and Rabe, Martin and Tschulik, Kristina
    and Scheu, Christina and Lim, Joohyun}, year={2022}, pages={24190–24198} }'
  chicago: 'Aymerich-Armengol, Raquel, Paolo Cignoni, Petra Ebbinghaus, Julia Linnemann,
    Martin Rabe, Kristina Tschulik, Christina Scheu, and Joohyun Lim. “Mechanism of
    Coupled Phase/Morphology Transformation of 2D Manganese Oxides through Fe Galvanic
    Exchange Reaction.” <i>Journal of Materials Chemistry A</i> 10, no. 45 (2022):
    24190–98. <a href="https://doi.org/10.1039/d2ta06552e">https://doi.org/10.1039/d2ta06552e</a>.'
  ieee: 'R. Aymerich-Armengol <i>et al.</i>, “Mechanism of coupled phase/morphology
    transformation of 2D manganese oxides through Fe galvanic exchange reaction,”
    <i>Journal of Materials Chemistry A</i>, vol. 10, no. 45, pp. 24190–24198, 2022,
    doi: <a href="https://doi.org/10.1039/d2ta06552e">10.1039/d2ta06552e</a>.'
  mla: Aymerich-Armengol, Raquel, et al. “Mechanism of Coupled Phase/Morphology Transformation
    of 2D Manganese Oxides through Fe Galvanic Exchange Reaction.” <i>Journal of Materials
    Chemistry A</i>, vol. 10, no. 45, Royal Society of Chemistry (RSC), 2022, pp.
    24190–98, doi:<a href="https://doi.org/10.1039/d2ta06552e">10.1039/d2ta06552e</a>.
  short: R. Aymerich-Armengol, P. Cignoni, P. Ebbinghaus, J. Linnemann, M. Rabe, K.
    Tschulik, C. Scheu, J. Lim, Journal of Materials Chemistry A 10 (2022) 24190–24198.
date_created: 2025-12-03T16:02:15Z
date_updated: 2025-12-03T16:30:43Z
department:
- _id: '985'
doi: 10.1039/d2ta06552e
extern: '1'
intvolume: '        10'
issue: '45'
keyword:
- manganese oxide
- nanomaterials
- TEM
- supercapacitors
language:
- iso: eng
main_file_link:
- open_access: '1'
oa: '1'
page: 24190-24198
publication: Journal of Materials Chemistry A
publication_identifier:
  issn:
  - 2050-7488
  - 2050-7496
publication_status: published
publisher: Royal Society of Chemistry (RSC)
quality_controlled: '1'
status: public
title: Mechanism of coupled phase/morphology transformation of 2D manganese oxides
  through Fe galvanic exchange reaction
type: journal_article
user_id: '116779'
volume: 10
year: '2022'
...