In Situ High-Pressure X-ray Diffraction and Raman Spectroscopy Study of Ti₃C₂T_x MXene

The lattice stability and phonon response of Ti₃C₂T_x MXene at high pressure are important for understanding its mechanical and thermal properties fully. Here, we use in situ high hydrostatic pressure X-ray diffraction (XRD) and Raman spectroscopy to study the lattice deformation and phonon behavior of Ti₃C₂T_x MXene. XRD spectra indicate that no phase transformation occurs up to the pressure of 26.7 GPa. The elastic constant along a lattice parameter was calculated to be 378 GPa. In the Raman spectra obtained at high-pressure, the out-of-plane phonon modes (A_1g at ~ 210, ~ 504, and ~ 711 cm^-1) exhibit monotonic blueshifts with increasing pressure. The Grüneisen parameters of these three modes were calculated to be 1.08, 1.16, and 0.29, respectively. These results enrich the basic property data of Ti₃C₂T_x MXene and would benefit the further understanding of this novel material.