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O: Fachverband Oberflächenphysik

O 76: Focus Session: 2D Transition Metal Carbides, Nitrides and Carbonitrides II (joint session DS/MM/O)

O 76.3: Talk

Thursday, March 21, 2024, 10:15–10:30, A 053

Hydrogenation as a mean to remove halogen functionalization from of Ti3C2Tz thin films — •Silvano Lizzit¹, Florian Brette^2,3, Hanna Pazniak⁴, Monika Shied¹, Paolo Lacovig¹, Florent Boucher³, Vincent Mauchamp², and Rosanna Larciprete⁵ — ¹Elettra-Sincrotrone Trieste, Trieste (I) — ²Uni. Poitiers, ISAE-ENSMA, CNRS, PPRIME, Poitiers (F) — ³CNRS-IMN, Nantes (F) — ⁴Uni. Grenoble Alpes, CNRS, Grenoble INP, Grenoble (F) — ⁵CNR- ISC, Roma (I)

The nature and the density of the chemical groups terminating the MXenes surface determine their electronic and chemical properties. Therefore, the manipulation of the surface termination allows to change the way these compounds interact with the surrounding environment. In this study we explored the possibility of using the functionalization with H atoms as a mean to modify the surface termination of T3C2Tz thin films. To this aim we used photoelectron spectroscopy with synchrotron radiation to investigate the surface reactions induced by the exposure to atomic hydrogen. Simulation of the valence band spectra by DFT calculations combined with the analysis of the core level spectra allowed us to elucidate the changes in the chemical bonding determined by the interaction with H atoms. It turned out that, in addition to the formation of C-H and -O-H bonds, sample hydrogenation removed the halogen terminating atoms, decreasing the F and Cl concentrations to less than 20% of the initial values. After removing the hydrogenated phases at 400 K, the dehydrogenated surface exhibited a chemical reactivity higher than that of the pristine sample.

Keywords: MXene; titanium carbide; XPS; DFT; hydrogenation