Scalable synthesis of high-purity Ti4N3Tx MXene via saturated salt solution (S3) etching

Abstract

Two-dimensional (2D) nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity; however, their synthesis remains challenging. Research has relied on traditional molten salt etching, highlighting the need for a scalable, high-purity approach. Here, we present the first solution-based synthesis of Ti4N3TxMXene via a novel saturated salt solution (S3) etching technique employing alkali metal salts. By optimizing the sintering process for high-purity Ti4AlN3 MAX and refining the S3 etching route, we significantly reduced the etch pit density to 1.2×106 cm− 2 and lowered the etch pit formation rate to 4 %, yielding high-quality, phasepure Ti4N3Tx MXene. Our study highlights the critical role of alkali metal ions in selective A-layer removal and demonstrates the impressive electrical conductivity and electromagnetic interference shielding performance of 2D nitride MXene, setting a new benchmark for this underexplored material. These findings pave the way for advancing 2D nitride MXenes and their diverse applications.