Advances in the Chemical Stabilization of MXenes.

MXenes are 2D nanomaterials with a wide array of possible compositions; they feature a unique combination of properties such as high electrical conductivity, hydrophilicity, and colloidal stability which makes them attractive for a variety of applications. However, the shelf life and industrial utility of MXenes face challenges due to their tendency to oxidize and disintegrate, particularly in dispersions. Thus, it is crucial to find effective ways to ensure the degradation stability of MXenes.

Exfoliation, delamination, and oxidation stability of molten salt etched NbCT MXene nanosheets.

Despite numerous prior reports of molten salt etching of MAX phases, few of these reports achieved water-dispersible MXene nanosheets, and none for Nb-based MXenes. Here we demonstrate the synthesis and aqueous dispersibility of NbCT nanosheets molten salt etching and utilizing a KOH wash to add hydroxyl surface groups. However, little is known about the oxidation of molten salt etched MXenes compared to acid-etched MXenes.

Water-dispersible Ti3C2Tz MXene nanosheets by molten salt etching.

Molten-salt etching of TiAlC MAX phase offers a promising route to produce 2D TiCT (MXene) nanosheets without hazardous HF. However, molten-salt etching results in MXene clays that are not water dispersible, thus preventing further processing. This occurs because molten-salt etching results in a lack of -OH terminal groups rendering the MXene clay hydrophobic.