Two-dimensional titanium carbide MXene produced by ternary cations intercalation via structural control with angstrom-level precision

Highly effective decontamination of lead is a primary challenge for ecosystem protection and public health. Herein, we report a methodology of ternary cations intercalation to synthesize Ti₃C₂T_x MXene by structural control with angstrom-level precision through mixed fluorinated salts wet etching-alkalization approach for high-efficient lead adsorption. The successive introduction of lithium, potassium, and sodium ions continuously weakens interaction forces between Ti₃C₂T_x layers, resulting in achieving fine tailored interlayer distance from 9.8 to 15.9 Å. A high density of complexing groups are formed after ternary cations intercalation, which greatly improve the hydrophilicity of Ti₃C₂T_x to enhance the accessibility and shorten the mass transfer and provide abundant adsorption sites to exhibit strong complexing effects with lead ions. The prepared ternary cations-intercalated Ti₃C₂T_x nanosheets exhibited a high adsorption capacity (267.2 mg/g) toward lead ions and sharply cut down lead concentration from 10 to 0.009 mg/L, far below the drinking water standards (0.015 mg/L).