XPS Binding Energy Shifts in 2D TiCT MXene go largely Beyond Intuitive Explanations: Rationalization from DFT Simulations and Experiments.

MXenes are prototypes of surface tunable 2D materials with vast potential for properties tuning. Accurately characterizing their surface functionalization and its role in electronic structure is crucial, X-ray photoelectron spectroscopy (XPS) being among the go-to methods to do so. Despite extensive use, XPS analysis remains however intricate.

Assessing the Surface Chemistry of 2D Transition Metal Carbides (MXenes): A Combined Experimental/Theoretical C Solid State NMR Approach.

The surface functionalization of 2D transition metal carbides or nitrides, so-called MXenes, is one of the fundamental levers allowing to deeply modify their physicochemical properties. Beyond new approaches to control this pivotal parameter, the ability to unambiguously assess their surface chemistry is thus key to expand the application fields of this large class of 2D materials. Using a combination of experiments and state of the art density functional theory calculations, we show that the NMR signal of the carbon─the element common to all MXene carbides and corresponding MAX phase precursors─is extremely sensitive to the MXene functionalization, although carbon atoms are not directly bonded to the surface groups.