A Simple Chemical Route via Ultrasonication‐Enabled In Situ HF Etching for Intercalant‐Free, Phase‐Pure MXene With Enhanced Interlayer Spacing

This study presents a facile synthesis of high‐quality, intercalant‐free Ti ₃ C ₂ T _x MXene through in situ HF generation using the LiF/HCl route and optimizes etchant amounts along with ultrasonication duration for enhanced interlayer spacing and complete phase transformation. In this study, the Ti ₃ AlC ₂ MAX phase was etched using varying LiF amounts (1.0, 1.5, and 2.0 g) combined with controlled ultrasonication duration (0 h, 0.5 h, and 1 h). Structural and morphological evolution of MXene was systematically examined using X‐ray diffraction, Rietveld refinement, cross‐sectional scanning electron microscopy (SEM), transmission electron microscope (TEM), and X‐ray photoelectron spectroscopy (XPS) analyses. The optimized sample synthesized using 1.5 g LiF and 1 h of ultrasonication exhibited complete removal of the Al layer, as evidenced by the disappearance of the (104) reflection and significant downshift of the (002) peak from 9.58° to 6.32°, indicating an expanded c‐lattice parameter of 28 Å. Cross‐sectional SEM and TEM analyses confirmed the formation of well‐defined accordion‐like multilayered morphology with defect‐free crystalline flakes, while XPS results validated the presence of Ti ⁺ , Ti ²⁺ , and Ti ⁴⁺ oxidation states with surface terminations (–O, –OH, –F) essential for functional tunability. The novelty of this work lies in the elimination of external intercalating agents and the reduced processing time, achieving a pure‐phase MXene with enhanced delamination efficiency. This optimized synthesis route presents a scalable, environmentally benign approach for tailoring MXene architecture, making it highly suitable for advanced energy storage, photocatalytic, and electrochemical applications.