Green synthesis strategy for Ti3C2 MXenes based on SnCl2-assisted etching with a small amount of HF

Abstract

This study developed a green synthesis strategy for Ti₃C₂ MXenes based on SnCl₂-assisted etching with trace low-concentration HF. The minimal HF solely served to remove surface oxides, facilitating the selective etching reaction between SnCl₂ and Ti₃AlC₂ (3Sn²⁺ + 2Al → 2Al³⁺ + 3Sn), yielding Ti₃C₂ with a characteristic accordion-like multilayered architecture. When employed as a supercapacitor working electrode in a 6 M KOH electrolyte, the material demonstrated a maximum specific capacitance of 186.725 F g⁻¹ at 0.5 A g⁻¹, significantly surpassing Ti₃C₂ electrodes prepared via conventional HF etching. This work provides a new avenue for the safe and controllable preparation of MXenes.