Exfoliation, delamination, and oxidation stability of molten salt etched Nb₂CT_<i>z</i> MXene nanosheets

Abstract

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 Nb₂CT_<i>Z</i> nanosheets <i>via</i> 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. Our results indicate slower oxidation behavior for MXenes etched by molten salts, which may be due to the decreased amount of oxygen-containing terminal groups.