Sandwich-like preparation of Ti3C2Tx@CoFe@TiO2 nanocomposites for high-performance electromagnetic wave absorption

Electromagnetic wave (EMW) absorbing materials have been widely applied in the fields of military and engineering areas. It is of great significance to develop high-performance EMW absorbing materials. This work assembled the sandwich-like Ti 3 C 2 T x based nanocomposites by the microwave-assisted annealing of CoFe-MOF@Ti 3 C 2 T x (CFMF@Ti 3 C 2 T x ) precursors at different temperatures. Results show that, as the heat treatment temperature is 450 °C, the sandwich-like Ti 3 C 2 T x @CoFe@TiO 2 nanocomposites present better EMW absorption properties. The minimum reflection loss (RL) value was −62.9 dB at 17.95 GHz with a thin thickness of 1.2 mm. Moreover, the effective absorption bandwidth (EAB) value was 5.02 GHz (12.74–17.76 GHz) with a thickness of 1.4 mm. The application of microwave-assisted annealing contributed to the formation of CoFe nanoparticles and TiO 2 nanoparticles because of the ultra-fast heating rate. The introduction of the nanoparticles enhanced the multiple polarization, optimized the impedance matching and introduced magnetic loss, leading to the improvement of EMW absorption. When the annealing temperature further increased to 550 °C, the EMW absorbing performance was weakened, which was mainly correlated with the decrement of the interface area due to the increase of the TiO 2 nanoparticle size and CoFe nanoparticle size. Thus, the loss effect of the multiple interface polarization weakens in the EMW absorption. In addition, the high permittivity of Ti 3 C 2 T x disappears, which deteriorated the impedance matching and attenuation ability of EMW. Ultimately, sandwich-like Ti 3 C 2 T x @CoFe@TiO 2 nanocomposite with satisfactory EMW absorbing properties is established, promising for various EMW absorbing applications.