Ordered double-M elements MXenes TiMC: Large in-plane stiffness and ferromagnetism

Investigation of Ordered TiMC and TiMCT2 (M = Cr and Mo; T = O and S) MXenes as High-Performance Anode Materials for Lithium-Ion Batteries

“…The optimized structural parameters and layer thickness of TiMC, TiMCT 2 (M = Cr, Mo; T = O, S), and their pristine mono-metal monolayers are listed in Table . The cell constant of the optimized unit cell structure for TiCrC is a = b = 2.934 Å and that for TiMoC is a = b = 3.086 Å, which is consistent with the previous work and is reasonable compared with that of their mono-metal monolayers (Ti 2 C, Cr 2 C, and Mo 2 C) . To determine the most stable configurations of the TiMCT 2 (M = Cr, Mo; T = O, S), nine possible configurations for all terminated modes were considered because of six possible high-symmetry positions for T (O and S) groups (Figure S1).…”

“…Because the TiVC monolayer was synthesized, we proposed that 2D TiMC (M = Cr and Mo) MXenes are stable with both thermal and dynamical stability and could be experimentally synthesized. The previous study has shown that 2D TiCrC and TiMoC monolayers exhibit a metallic-like property and good electronic conductivity and have proven their stabilities theoretically . In addition, the functionalized derivatives have been formed during MXene synthesis and have been studied theoretically or experimentally.…”

Synthesis and Surface Chemistry of 2D TiVC Solid-Solution MXenes

“…Until now, the large majority of studies have focused on the synthesis and delamination of mono-M element MXenes. ,− However, it is known that utilizing a combination of elements in the M site, either as solid solutions or in an ordered phase, may provide an effective method to tune the properties of MXenes. , Synthesis of two solid-solution M 2 X-type MXenes has been reported; the stacked TiNbCT x MXene was synthesized using 50% HF and its delamination was achieved using hydrazine, , and stacked TiVCT x MXene was produced recently by a mixture of lithium fluoride salt (LiF) and hydrochloric acid (HCl) . It is worth noting that the majority of synthesized MXenes were created using a high concentration of HF in the etching process, which is far from ideal from a safety perspective and also affects the quality, surface chemistry, and properties of the resultant MXenes. , …”

Double transition-metal MXenes: Atomistic design of two-dimensional carbides and nitrides

“…69 Both effects are further influenced by interactions of M′ and M″ elements with surface terminations, 55,69 where a larger difference in electronegativity between transition metals and surface is predicted while metallic behavior is predicted in Ti3C2O2. 76 (e) The electronic band structure of W2HfC2O2, which highlights the bandgap induced by accounting for spin-orbit coupling (SOC) of electrons in the d-orbital of M′ and M″ in the analysis. 55 (f) Ferromagnetism (FM) and antiferromagnetism (AFM) is seen in theoretical out-of-plane DTM MXenes.…”

“…74 Similar to the electronic properties, the magnetic behavior of ordered MXenes is controlled by both M′ and M″ elements. 64,68,75,76 To date, M′ = Ti, Hf, Cr, and M″ = Mn, V have been explored by first-principles methods for magnetic out-of-plane DTM MXenes. Some of these DTM MXenes have been predicted to be ferromagnetic regardless of surface termination, such as Ti2MnC2Tx (Figure 4f).…”