Rapid and direct growth of bipyramid TiO2 from Ti3C2Tx MXene to prepare Ni/TiO2/C heterogeneous composites for high-performance microwave absorption

The layered structure with large specific area and moderate conductivity endow MXene with desired properties for microwave absorption. To date, oxidation of two dimensional (2D) Ti3C2Tx to obtain composites including TiO2 and C usually proceed under complex process, which impedes their further development. Herein, Ni/TiO2/C heterogeneous composites were synthesized in one pot reaction within a short time (10 min) by microwave irradiation of an aqueous mixture of nickel chloride and hexadecyltrimethylammonium bromide (CTAB) functionalized Ti3C2Tx MXene. This simple one-pot microwave-assisted method is beneficial to obtain uniform TiO2 nanoparticles with different morphologies (bipyramid and irregular) embedded in C layers, and the expanded interlayer originated from the intercalation of TiO2 and Ni nanoparticles. In addition, the growth mechanism and different morphologies of TiO2 from Ti3C2Tx MXene are discussed. The elaborately designed laminar Ni/TiO2/C composites can be used as light and high efficient microwave absorption materials due to the synergistic effect of dielectric loss, magnetic loss and unique 2D heterogeneous nanostructure. The minimum reflection loss (RL) of -39.91 dB was obtained at 16.93 GHz with a thickness of only 1.4 mm. In addition, the dissipating heat ability of Ni/TiO2/C composites coated on lab-gown cloth was investigated via thermal infrared images. This work provides a simple and effective strategy for preparing other MXene-based heterogeneous composites.