Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

In Situ X-ray Diffraction Study of MXene Synthesis by the Reaction of Ti3AlC2 with Molten Zinc and Tin Chlorides

Iakunkov, Artem ; Boulanger, Nicolas ; Gurzeda, Bartosz ; Li, Gui ; Hennig, Christoph ; Svitlyk, Volodymyr ; Jørgensen, Mads Ry Vogel LU orcid ; Kantor, Innokenty LU ; Baburin, Igor A. and Hamedi, Mahiar Max , et al. (2025) In Chemistry of Materials 37(3). p.1132-1142
Abstract

Using molten salts for etching aluminum (Al) away from the MAX phase for MXene synthesis is an attractive alternative method that allows one to avoid the use of toxic hydrofluoric acid (HF) solutions. However, the mechanism of the MAX phase reaction with molten salts remains to date unclear due to the lack of in situ data. Here, we present a detailed in situ time-resolved synchrotron radiation X-ray diffraction study of the MAX phase annealing in molten ZnCl2 and SnCl2. The reaction of salts with the MAX phase is found to occur in two stages. The initial period of annealing results in the delamination of two-dimensional (2D) Ti3C2 layers, vigorous evolution of AlCl3 bubbles, and... (More)

Using molten salts for etching aluminum (Al) away from the MAX phase for MXene synthesis is an attractive alternative method that allows one to avoid the use of toxic hydrofluoric acid (HF) solutions. However, the mechanism of the MAX phase reaction with molten salts remains to date unclear due to the lack of in situ data. Here, we present a detailed in situ time-resolved synchrotron radiation X-ray diffraction study of the MAX phase annealing in molten ZnCl2 and SnCl2. The reaction of salts with the MAX phase is found to occur in two stages. The initial period of annealing results in the delamination of two-dimensional (2D) Ti3C2 layers, vigorous evolution of AlCl3 bubbles, and dissolution of Zn in a ZnCl2 melt. The chlorine-terminated Ti3C2 sheets formed in the delaminated state are restacked into a relatively well-ordered MXene structure (P63/mmc, a = 3.071 Å and c = 18.577 Å) during the prolonged annealing in molten salts. Surprisingly, the data recorded directly in molten salts at temperatures up to 873 K demonstrate that Ti3C2Clx MXene shows no swelling in both liquid ZnCl2 and SnCl2. The structure of MXene studied directly in the molten salts is found to be the same as in ex situ experiments performed after cooling and water washing under ambient conditions. The absence of the “pristine” melt-swollen phase indicates a rather different mechanism of MXene formation compared to HF-based solution methods. Formation of MXene by gradually removing Al from the MAX phase starting at the edges of flakes and propagating into the deeper parts of interlayers is not possible, since the molten salt is not capable of penetrating between Cl-terminated Ti3C2 layers.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Chemistry of Materials
volume
37
issue
3
pages
11 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85215866707
ISSN
0897-4756
DOI
10.1021/acs.chemmater.4c02989
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 The Authors. Published by American Chemical Society.
id
f0c32a30-068c-494f-850f-23ff2f148a2d
date added to LUP
2025-04-10 09:04:06
date last changed
2025-04-10 09:05:00
@article{f0c32a30-068c-494f-850f-23ff2f148a2d,
  abstract     = {{<p>Using molten salts for etching aluminum (Al) away from the MAX phase for MXene synthesis is an attractive alternative method that allows one to avoid the use of toxic hydrofluoric acid (HF) solutions. However, the mechanism of the MAX phase reaction with molten salts remains to date unclear due to the lack of in situ data. Here, we present a detailed in situ time-resolved synchrotron radiation X-ray diffraction study of the MAX phase annealing in molten ZnCl<sub>2</sub> and SnCl<sub>2</sub>. The reaction of salts with the MAX phase is found to occur in two stages. The initial period of annealing results in the delamination of two-dimensional (2D) Ti<sub>3</sub>C<sub>2</sub> layers, vigorous evolution of AlCl<sub>3</sub> bubbles, and dissolution of Zn in a ZnCl<sub>2</sub> melt. The chlorine-terminated Ti<sub>3</sub>C<sub>2</sub> sheets formed in the delaminated state are restacked into a relatively well-ordered MXene structure (P6<sub>3</sub>/mmc, a = 3.071 Å and c = 18.577 Å) during the prolonged annealing in molten salts. Surprisingly, the data recorded directly in molten salts at temperatures up to 873 K demonstrate that Ti<sub>3</sub>C<sub>2</sub>Cl<sub>x</sub> MXene shows no swelling in both liquid ZnCl<sub>2</sub> and SnCl<sub>2</sub>. The structure of MXene studied directly in the molten salts is found to be the same as in ex situ experiments performed after cooling and water washing under ambient conditions. The absence of the “pristine” melt-swollen phase indicates a rather different mechanism of MXene formation compared to HF-based solution methods. Formation of MXene by gradually removing Al from the MAX phase starting at the edges of flakes and propagating into the deeper parts of interlayers is not possible, since the molten salt is not capable of penetrating between Cl-terminated Ti<sub>3</sub>C<sub>2</sub> layers.</p>}},
  author       = {{Iakunkov, Artem and Boulanger, Nicolas and Gurzeda, Bartosz and Li, Gui and Hennig, Christoph and Svitlyk, Volodymyr and Jørgensen, Mads Ry Vogel and Kantor, Innokenty and Baburin, Igor A. and Hamedi, Mahiar Max and Talyzin, Alexandr V.}},
  issn         = {{0897-4756}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{3}},
  pages        = {{1132--1142}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Chemistry of Materials}},
  title        = {{In Situ X-ray Diffraction Study of MXene Synthesis by the Reaction of Ti<sub>3</sub>AlC<sub>2</sub> with Molten Zinc and Tin Chlorides}},
  url          = {{http://dx.doi.org/10.1021/acs.chemmater.4c02989}},
  doi          = {{10.1021/acs.chemmater.4c02989}},
  volume       = {{37}},
  year         = {{2025}},
}