  2D materials are emerging as promising nanomaterials for applications in
energy storage and catalysis. In the wet chemical synthesis of MXenes, these 2D
transition metal carbides and nitrides are terminated with a variety of
functional groups, and cations such as Li+ are often used to intercalate into
the structure to obtain exfoliated nanosheets. Given the various elements
involved in their synthesis, it is crucial to determine the detailed chemical
composition of the final product, in order to better assess and understand the
relationships between composition and properties of these materials. To
facilitate atom probe tomography analysis of these materials, a revised
specimen preparation method is presented in this study. A colloidal Ti3C2Tz
MXene solution was processed into an additive-free free-standing film and
specimens were prepared using a dual beam scanning electron microscope /
focused ion beam. To mechanically stabilize the fragile specimens, they were
coated using an in situ sputtering technique. As various 2D material inks can
be processed into such free-standing films, the presented approach is pivotal
for enabling atom probe analysis of other 2D materials.
