Synthesis of two-dimensional titanium nitride Ti₄N₃(MXene)

TLDR

The study reports the synthesis of the first two‑dimensional Ti4N3 MXene. Ti4N3 MXene was produced by molten fluoride salt etching of Ti4AlN3 at 550 °C under argon, followed by delamination into few‑layer nanosheets and DFT calculations to identify the most stable surface terminations. Density functional theory predicts that Ti4N3 is metallic, with bare Ti4N3 exhibiting magnetism that is significantly diminished upon surface functionalization.

Abstract

We report on the synthesis of the first two-dimensional transition metal nitride, Ti4N3-based MXene. In contrast to the previously reported MXene synthesis methods – in which selective etching of a MAX phase precursor occurred in aqueous acidic solutions – here a molten fluoride salt is used to etch Al from a Ti4AlN3 powder precursor at 550 °C under an argon atmosphere. We further delaminated the resulting MXene to produce few-layered nanosheets and monolayers of Ti4N3Tx, where T is a surface termination (F, O, or OH). Density functional theory calculations of bare, non-terminated Ti4N3 and terminated Ti4N3Tx were performed to determine the most energetically stable form of this MXene. Bare and functionalized Ti4N3 are predicted to be metallic. Bare Ti4N3 is expected to show magnetism, which is significantly reduced in the presence of functional groups.