Saleesha Sin

Two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides (MXenes) were discovered in 2011. Since the original discovery, more than 20 different compositions have been synthesized by the selective etching of MAX phase and other precursors and many more theoretically predicted. They offer a variety of different properties, making the family promising candidates in a wide range of applications, such as energy storage, electromagnetic interference shielding, water purification, electrocatalysis, and medicine. These solution-processable materials have the potential to be highly scalable, deposited by spin, spray, or dip coating, painted or printed, or fabricated in a variety of ways. Due to this promise, the amount of research on MXenes has been increasing, and methods of synthesis and processing are expanding quickly. The fast evolution of the material can also be noticed in the wide range of synthesis and processing protocols that determine the yield of delamination, as well as the quality of the 2D flakes produced. Here we describe the experimental methods and best practices we use to synthesize the most studied MXene, titanium carbide (Ti3C2Tx), using different etchants and delamination methods. We also explain effects of synthesis parameters on the size and quality of Ti3C2Tx and suggest the optimal processes for the desired application.

This chapter describes the experimental methods and best practices to synthesize the most studied MXene, titanium carbide, using different etchants and delamination methods. It explains effects of synthesis parameters on the size and quality of Ti3C2Tx and suggests the optimal processes for the desired application. Using intercalating compounds to expand the interlayer spacing of Ti3C2Tx flakes has proven to be a key step for weakening the interactions between 2D layers and delaminating MXene into separate 2D sheets. The intercalation and delamination process typically requires a suitable solvent for the material and intercalant, a mixing step where the intercalant is introduced between 2D sheets, occasionally a sonication step depending on desired flake size and concentration. Additionally, since MXenes can be redispersed in different solvents, another practice to store MXenes is to filter the colloidal solution and store the resulting film under vacuum.