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Title: A first-principles study of multilayer Ti 3 C 2 T x MXene model
We proposed a more realistic albeit slightly complicated multilayer Ti3C2Tx model and performed a comprehensive theoretical study of its structural and electronic properties. In this work, we constructed various multilayer Ti3C2Tx structures considering different concentrations of hydrofluoric acid (HF; 5, 10, and 48 wt%) as the etchant. The validity of our ternary mixed O/OH/F-terminated Ti3C2Tx multilayer models is confirmed by the consistency of the calculated d-spacing (9.60 ± 0.07 Å), simulated X-ray diffraction (XRD) spectra and the predicted adhesion energy (0.77 ± 0.15 J m−2) with the reported experimental measurements. The uniform terminated and mixed terminated multilayer Ti3C2Tx exhibit metallic characteristics, similar to those of monolayer Ti3C2Tx. We found a stronger interaction between the interlayers with OH-rich ternary mixed terminated Ti3C2Tx surfaces, due to the formation of hydrogen bonds between the hydroxyl groups and adjacent layers of F/O terminal groups as supported by the crystal orbital Hamilton population (COHP) calculation. From this finding, we propose that multilayer Ti3C2Tx etched with a strong HF acid could be easily exfoliated into monolayer sheets due to smaller adhesion energy. Based on this work, we believe that the current findings will offer a fundamental understanding and a useful baseline multilayer model for the future investigation of the hydrogen and ion storage and diffusion properties in the MXene multilayer application.  more » « less
Award ID(s):
2117956
PAR ID:
10548390
Author(s) / Creator(s):
;
Publisher / Repository:
RSC Publishing
Date Published:
Journal Name:
Nanoscale
ISSN:
2040-3364
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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