Synthesis and electromagnetic wave absorption of novel Mo.sub.2TiC.sub.2T.sub.x MXene with diverse etching methods

Mo.sub.2TiC.sub.2T.sub.x, a rising sort of 2D MXenes, ought to be a promising wave-absorbing material to solve the electromagnetic wave contamination these days attributable to its interesting laminar structure. However, there was a lack of systematic research on Mo.sub.2TiC.sub.2T.sub.x in the field of microwave absorbing materials. In this work, Mo.sub.2TiC.sub.2T.sub.x MXenes were synthesized by the current common etching method of LiF/HCl or HF kept at 50 °C for 48 h. The microscopic morphology was investigated by XRD, XPS, SEM, EDS, TEM and HRTEM, indicating that the product etched by pure HF possessed the maximum interlaminar space. Subsequently, the electromagnetic wave (EMW) absorbing performances of the Mo.sub.2TiC.sub.2T.sub.x MXenes were systematically evaluated for the first time. Likewise, the Mo.sub.2TiC.sub.2T.sub.x MXene etched by pure hydrofluoric acid (S3) demonstrated high EMW absorption properties, and the minimal reflection loss value is - 25.39 dB (1.6 mm, thickness) corresponding to 17.04 GHz with the bandwidth of 3.2 GHz within the extent of 14.8-18 GHz. This is due to well-matched impedance and multiple loss mechanisms, such as dipole polarization, conduction loss and multiple scattering and reflection through the layered structure by the HF-etching treatment. This study additional grows the 2D MXene materials family by advertising various properties, particularly electromagnetic wave absorption performance. Graphical abstract