AI Article Synopsis
- Two-dimensional (2D) materials, like cobalt oxide, are gaining attention due to their unique properties and potential applications, but their formation processes are not fully understood.
- Initial observations show that 3D nanoparticles form from a molecular precursor before transitioning into 2D nanosheets.
- The study reveals that the transformation is influenced by energy changes as the nanocrystals grow, which can inform future material design and synthesis methods in solutions.
Article Abstract
Two-dimensional (2D) materials have attracted significant interest because of their large surface-to-volume ratios and electron confinement. Compared to common 2D materials such as graphene or metal hydroxides, with their intrinsic layered atomic structures, the formation mechanisms of 2D metal oxides with a rocksalt structure are not well understood. Here, we report the formation process for 2D cobalt oxide and cobalt nickel oxide nanosheets, after analysis by in situ liquid-phase transmission electron microscopy. Our observations reveal that three-dimensional (3D) nanoparticles are initially formed from the molecular precursor solution and then transform into 2D nanosheets. Ab initio calculations show that a small nanocrystal is dominated by positive edge energy, but when it grows to a certain size, the negative surface energy becomes dominant, driving the transformation of the 3D nanocrystal into a 2D structure. Uncovering these growth pathways, including the 3D-to-2D transition, provides opportunities for future material design and synthesis in solution.
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| http://dx.doi.org/10.1038/s41563-019-0415-3 | DOI Listing |
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