Mechanistic Insight into the Chemical Exfoliation and Functionalization of Ti3C2 MXene

• DOI: 10.1021/acsami.6b08413
• Publication Date: 2016-08-18T16:13:23Z
• Authors: Pooja Srivastava; Avanish Mishra; Hiroshi Mizuseki; Kwang-Ryeol Lee; Abhishek K. Singh
• Keywords: MXenes; Surface Modification; Exfoliation joint; MAX phases; Electron localization function

MXene, a two-dimensional layer of transition metal carbides/nitrides, showed great promise for energy storage, sensing, and electronic applications. MXene are chemically exfoliated from the bulk MAX phase; however, mechanistic understanding exfoliation subsequent functionalization these technologically important materials is still lacking. Here, using density-functional theory we show that Ti3C2 proceeds via HF insertion through edges Ti3AlC2 phase. Spontaneous dissociation termination edge Ti atoms by H/F weakens Al-MXene bonds. Consequent opening interlayer gap allows further leads to formation AlF3 H2, which eventually come out MAX, leaving fluorinated behind. Density state electron localization function shows robust binding between F/OH Ti, makes it very difficult obtain controlled functionalized or pristine MXene. Analysis calculated Gibbs free (ΔG) fully be lowest in energy, whereas thermodynamically least favorable. In presence water, mixed Ti3C2Fx(OH)1-x (x ranges 0 1) can obtained. The ΔG values MXenes close indicating random nonuniform microscopic gained here unveils challenges controlling essential its practical application.