Frontcover of Dalton Transactions
New investigations on the exfoliabiltiy of maxenes
2020/09/18 by K. Albe
Ali Malik investigated the exfoliability of maxenes using DFT calculations. The results were published together with the C. Birkels group. The paper appeared on the front page of Dalton Transactions.
Two-dimensional carbides / nitrides, typically called MXenes, are a member of the growing family of two-dimensional materials. The prediction of a ferromagnetic ground state in chromium-containing MXenes has sparked a growing interest in their chemical exfoliability from Cr-based MAX phases. However, the exfoliation behavior poses serious difficulties when using standard etchants such as hydrofluoric acid (HF). Here we investigate the exfoliation of Cr2GaC particles by chemical etching with aqueous HF, both experimentally and theoretically. Structure and microstructure analyzes show that the Cr2GaC particles decompose into chromium carbide and oxide without the formation of a Cr-based MXene. A thermodynamic analysis based on electronic ab initio structure calculations shows that the exfoliability of Cr-based MXen from Cr2GaC by HF etching is inhibited by more favorable competitive reactions. This result confirms the experimental finding and suggests that HF is an unsuitable etchant for Cr2GaC.
Read more:
https://pubs.rsc.org/en/content/articlelanding/2020/dt/d0dt01448f#!divAbstract
