Halogen Etch of Ti3AlC2 MAX Phase for MXene Fabrication

The versatile property suite of two-dimensional MXenes is driving interest in various applications, including energy storage, electromagnetic shielding, and conductive coatings. Conventionally, MXenes are synthesized by a wet-chemical etching of the parent MAX-phase in HF-containing media. The acute toxicity of HF hinders scale-up, and competing surface hydrolysis challenges control of surface composition and grafting methods. Herein, we present an efficient, room-temperature etching method that utilizes halogens (Br-2, I-2, ICl, IBr) in anhydrous media to synthesize MXenes from Ti3AlC2. A radical-mediated process depends strongly on the molar ratio of the halogen to MAX phase, absolute concentration of the halogen, the solvent, and temperature. This etching method provides opportunities for controlled surface chemistries to modulate MXene properties.

Automated summary

A new room-temperature etching method using halogens in anhydrous media can synthesize MXenes from Ti3AlC2, providing opportunities for controlled surface chemistries to modulate MXene properties. The radical-mediated process strongly depends on various factors, such as the molar ratio of halogen to MAX phase, concentration of halogen, solvent, and temperature.