Facilitating Atom Probe Tomography of 2D MXene Films by In Situ Sputtering

TL;DR

This paper introduces a new specimen preparation method using in situ sputtering to enable atom probe tomography of fragile 2D MXene films, aiding detailed compositional analysis.

Contribution

A novel in situ sputtering technique for stabilizing 2D MXene specimens for atom probe tomography analysis.

Findings

Successful preparation of stable MXene specimens for atom probe analysis.

Enhanced ability to analyze chemical composition of 2D MXene materials.

Method applicable to other 2D materials for detailed characterization.

Abstract

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.