Two-dimensional MXene Ti3C2 produced by exfoliation of Ti3AlC2

MXene, a new family of 2D materials, possesses excellent electrical conductivity and hydrophilicity. To date, the majority of MXenes are only successfully produced by exfoliating the MAX phases with high concentration hydrofluoric acid (HF). In this study, the 2D MXene Ti₃C₂ with larger interplanar spacing was successfully obtained by etching Ti₃AlC₂ with bifluoride (NaHF₂, KHF₂, NH₄HF₂) in single-stage process. The morphology, structure and element composition of prepared Ti₃C₂ samples were characterized by scanning electron smicroscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS). The synthesis mechanism of Ti₃C₂ was elaborately demonstrated. The possible reaction equations between Ti₃AlC₂ and different bifluorides were generalized, indicating the formation of hydrosoluble by-products of Na₃AlF_6, K₃AlF₆ and (NH₄)₃AlF₆. This work presents a safely effective method to synthesize the 2D nanocrystals MXene.