Self-Assembled Sandwich-like MXene-Derived Nanocomposites for Enhanced Electromagnetic Wave Absorption.

Sandwich-like MXene/FeO and C/TiO/α-Fe two-dimensional (2D) nanocomposites were fabricated via in situ hydrothermal assembly of FeO nanoparticles on MXene nanosheets and postannealing. The as-prepared sandwich-like MXene/FeO nanocomposites contain uniformly distributed FeO nanoparticles between the interlayers of the 2D MXene TiCT nanoflakes. The redox reaction, TiCT + FeO → 3TiO + 2C + 3Fe, has also been reported for the first time to transform the binary MXene/FeO nanocomposites into ternary C/TiO/α-Fe nanocomposites with the 2D structure maintained intact. Such a transition during postannealing gives rise to further enhanced electromagnetic wave absorption compared with that of the MXene/FeO nanocomposites on top of the already improved performance of the MXene/FeO compared with that of pristine MXene. The 2D C/TiO/α-Fe nanocomposites exhibit effective absorption bandwidths of 3.3 and 3.5 GHz at thicknesses of 1 and 1.5 mm, respectively. This work offers a new route for fabricating novel electromagnetic wave absorbers, and the fine balance among lightweight, broad band, and small thickness of the C/TiO/α-Fe nanocomposites makes them promising in the field of electromagnetic wave absorption.