Electronic and vibrational properties ofV2C-based MXenes: From experiments to first-principles modeling

Abstract

In the present work, the electronic and vibrational properties of both pristine V 2 C and fullyterminated V 2 CT 2 (where T = F, O, OH) 2D monolayers are investigated using density functional theory. Firstly, the atomic structures of V 2 C-based MXene phases are optimized and their respective dynamical stabilities are discussed. Secondly, electronic band structures are computed indicating that V 2 C is metallic as well as all the corresponding functionalized systems. Thirdly, the vibrational properties (phonon frequencies and spectra) of V 2 C-based MXenes are computed thanks to density functional perturbation theory and reported for the first time. Both Raman (E g , A 1g ) and infrared active (E u , A 2u ) vibrational modes are predicted ab initio with the aim to correlate the experimental Raman peaks with the calculated vibrational modes and to assign them with specific atomic motions. The effect of the terminal groups on the vibrational properties is emphasized as well as on the presence and position of the corresponding Raman peaks. Our results provide new insights for the identification and characterization of V 2 C-based samples using Raman spectroscopy.

Precious‐Metal‐Free Electrocatalysts for Activation of Hydrogen Evolution with Nonmetallic Electron Donor: Chemical Composition Controllable Phosphorous Doped Vanadium Carbide MXene

“…For pristine V 2 CT x (bottom line in Figure S2, Supporting Information), the bands of bulk‐V 2 AlC MAX phase at 157 cm −1 ( E 2g ), 239 cm −1 ( E 2g ), 258 cm −1 ( E 1g ), and 364 cm −1 ( A 1g ) are vanished and new bands appear at 139, 198, 224 ( E g ), 350–400 cm −1 , and 506 cm −1 ( A 1g ). These results are comparable with the previous results in Raman spectra study of V‐based MXene . It should be noted here that the peaks appear more clearly as the reaction temperature increases (P1‐, P2‐, and P3‐V 2 CT x ).…”

Carbon dioxide adsorption of two-dimensional carbide MXenes

“…For V 2 CT x , the bands of V 2 AlC at 157, 239, 257, and 364 cm -1 [41] are vanished and new bands appear at 139, 254, 490, and 667 cm -1 . This spectrum is similar with the reported spectrum of V 2 C MXene in a very recent literature [42]. Thus, V 2 CT x is successfully synthesized.…”

Prelithiated V2C MXene: A High‐Performance Electrode for Hybrid Magnesium/Lithium‐Ion Batteries by Ion Cointercalation

“…According to the previous experience, the purity of V 2 C in this work is > 90%. In addition, Raman spectra of the V 2 AlC and V 2 C nanosheets are offered in Figure S3 (Supporting Information), the peaks of ω 1 –ω 4 belong to V 2 AlC phase due to the vibrations of Al atom in V 2 AlC, which vanish after the etching treatment. Meanwhile, new peaks at ≈145, ≈196, ≈282, and ≈410 cm −1 appear in the V 2 C spectrum.…”