The A element of a parent MAX phase is usually etched to create the MXenes family of two-dimensional (2D) materials. The most common method for obtaining them is to selectively etch three-dimensional (3D) parent materials in an acidic environment. One unanswered question is whether additional layered materials can be produced using current chemical techniques.
Researchers at Linköping University have now developed a method that enables the synthesis of hundreds of new 2D materials. Their method predicts other three-dimensional materials suitable for conversion into 2D materials. Plus, they proved that the theoretical model is consistent with reality.
The researchers employed a three-step procedure to be successful. They first created a theoretical model to determine which parent materials would be appropriate. From a database and a selection of 66,643 materials, researchers discovered 119 interesting 3D materials using large-scale simulations at the National Supercomputer Centre.
Researchers went further to create the material in the lab. Out of 119 possible materials, they studied which ones had the required chemical stability and which were the best candidates. They started with synthesizing the 3D material, which was a challenge. Finally, they had a high-quality sample where they could exfoliate and etch away specific atom layers using hydrofluoric acid.
Two-dimensional Ru2SixOy was formed when the researchers extracted yttrium (Y) from the parent material YRu2Si2.
However, in step three, verification is required to validate success in the lab. The researchers utilized the Arwen scanning transmission electron microscope at Linköping University. It is capable of analyzing materials and their atomic structures. In Arwen, spectroscopy can also be used to examine the individual atoms that make up a material.
Jonas Björk, associate professor at the Division of Materials Design, said, “We were able to confirm that our theoretical model worked well and that the resulting material consisted of the correct atoms. After exfoliation, images of the material resembled the pages of a book. Amazingly, the theory could be put into practice, thereby expanding the concept of chemical exfoliation to more materials families than MXenes.”
Thanks to the researchers’ discovery, many additional 2D materials with distinctive features are now possible. They can then serve as the basis for endless technical applications. The researchers’ next action is to expand the experimentation and investigate more promising precursor materials. Future uses, in Johanna Rosén’s opinion, are practically limitless.
Johanna Rosén, a professor of Materials physics at Linköping University, said, “In general, 2D materials have shown great potential for an enormous number of applications. You can imagine capturing carbon dioxide or purifying water, for example. Now, it’s about scaling up the synthesis and doing it in a sustainable way.”
Journal Reference:
- Jonas Björk, Jie Zhou, Per O. Å. Persson and Johanna Rosen. Two-dimensional materials by large-scale computations and chemical exfoliation of layered solids. Science. DOI: 10.1126/science.adj6556