Solvent-regulated preparation of well-intercalated Ti 3 C 2 T x MXene nanosheets and application for highly effective electromagnetic wave absorption

Abstract MXene-derived nanostructures provide the possibility of meeting the requirements of strong absorption, thin thickness and flexible layer for electromagnetic (EM) wave absorption. However, exploration of pure and well-intercalated MXene nanosheets for efficient EM wave absorption is still in the nascent stages. Herein, Ti 3 C 2 T x nanosheets with solvent-manipulated properties were achieved via ultrasonication-solvothermal treatment of bulk Ti 3 C 2 T x in different solvents including dimethylformamide (DMF), ethanol, and dimethyl sulfoxide (DMSO), respectively, because of their combined influences of molecular size, oxidation capability, and boiling point. Especially, it was found that a larger layer space and less oxidation effects on the Ti 3 C 2 T x nanosheets were observed upon solvothermal treatment in DMF than those in ethanol or DMSO treatment. As a result, the DMF-treated Ti 3 C 2 T x nanosheets can be used as highly effective dielectric materials for EM wave absorption. The reflection loss value reached −41.9 dB (more than 99.99%) at 13.4 GHz with the sample thickness of only 1.1 mm. Characterization techniques including scanning electron microscopy, transmission electron microscopy, atomic force microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and density functional theory calculation were used to elaborate the possible mechanisms.