Chalcogen and halogen surface termination coverage in MXenes—structure, stability, and properties

Autor: Martin Dahlqvist, Johanna Rosen
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: npj 2D Materials and Applications, Vol 8, Iss 1, Pp 1-13 (2024)
Druh dokumentu: article
ISSN: 2397-7132
DOI: 10.1038/s41699-024-00502-8
Popis: Abstract MXenes are a diverse family of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides. They can be synthesized through both top-down approaches, such as selective etching of A-layers from MAX phases using acids or molten salts, and bottom-up approaches, such as direct synthesis using chemical vapor deposition. However, the degree of the surface termination coverage depends on the synthesis route and is one key parameter for controlling its properties. This study focuses on halogen- and chalcogen-terminated MXenes, particularly M2CT x where M = Ti, Zr, V, Nb, Ta, and T = S, Se, Te, Cl, Br, I, and with surface termination coverage ranging from 100% (ideal, x = 2) to 50% (x = 1). The incorporation of oxygen on vacant termination sites was also evaluated. Using density functional theory (DFT) calculations, we investigated the structural, electronic, and mechanical properties of these MXenes. Our findings reveal that non-ideal termination coverage (x
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