Stabilising intrinsic room-temperature ferromagnetic two-dimensional semimetallic Cr 2CT x MXene by epitaxial self-intercalation of H 2O-etched Cr 2(AlLi)C

Physical properties, such as electrochemical and electromagnetic properties, of two-dimensional MXenes can be improved by enhancing their stability. However, MXenes fabricated via acid etching contain defects, which affect their physical properties. In this study, a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is proposed. The fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H2O-etched Cr2(AlLi)C. On the basis of this mechanism, the room-temperature ferromagnetism of two-dimensional few-layered Cr2CTx MXenes, which has a specific saturation magnetization of ~0.26 emu/g and a Curie temperature of > 353 K, is experimentally verified. The calculated electronic band structure implies that the semimetal Cr2CTx MXene has a band gap of 0.75 eV. This study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.