Molten Salt Assisted Synthesis and Oxidation Kinetics of Water-Dispersible Ti3C2Tx and Nb2CTx MXene Nanosheets

Despite numerous prior reports of molten salt etching of MAX phases, there have been few successful reports of water-dispersible MXene nanosheets, and none for Nb-based MXenes. We recently demonstrated that molten salt etching can be used to create water-dispersible Ti3C2Tx nanosheets. Here we demonstrate the synthesis and aqueous dispersion of Nb2CTx nanosheets via molten salt etching by utilizing a KOH wash to add hydroxyl group to obtain water-dispersible Nb2CTx nanosheets. However, little is known about the oxidation of molten salt etched MXenes compared to acid-etched MXenes. Our results indicate slower oxidation kinetics for MXenes etched by molten salts, which may be due to the decreased amount of oxygen-containing terminal groups.