Facile preparation of Ti3C2Tx sheets by selectively etching in a H2SO4/H2O2 mixture

Abstract

MXenes and MXene-based composite materials have potential applications in a wide range of areas due to their unique physical and chemical characteristics. At present, it is still a major challenge to develop a simple, safe, and efficient route to prepare MXenes without using fluorinated etchants. Herein, we design a facile method to prepare Ti 3 C 2 T x MXene sheets by selectively etching Ti 3 AlC 2 powders in an aqueous diluted H 2 SO 4 solution with H 2 O 2 as an oxidant. In a system of H 2 SO 4 and H 2 O 2 , an aqueous H 2 SO 4 solution with a concentration of 6 mol/L is a strongly acidic medium with no volatility, and 30% H 2 O 2 acts as a strong green oxidizer without harmful by-products. The experimental process is safe and convenient to conduct in a beaker under a water bath of 40°C. The etching process can be completed in 1 h under the air atmosphere conditions. The experimental results confirmed that the etched Ti 3 AlC 2 powders can be successfully separated into Ti 3 C 2 T x nanosheets under ultrasound treatment without using any intercalation agent. The relevant etching mechanism is may be attributed to the synergy effect of H 2 SO 4 and H 2 O 2 , which triggers sequential selective etching of Al layers from the Ti 3 AlC 2 phase. It may provide a new green way to prepare MXene-based materials without using toxic HF or HF-containing etchants.