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

Sandwich-like MXene/Fe3O4 and C/TiO2/α-Fe two-dimensional (2D) nanocomposites were fabricated via in situ hydrothermal assembly of Fe3O4 nanoparticles on MXene nanosheets and postannealing. The as-prepared sandwich-like MXene/Fe3O4 nanocomposites contain uniformly distributed Fe3O4 nanoparticles between the interlayers of the 2D MXene Ti3C2T x nanoflakes. The redox reaction, Ti3C2T x + Fe3O4 → 3TiO2 + 2C + 3Fe, has also been reported for the first time to transform the binary MXene/Fe3O4 nanocomposites into ternary C/TiO2/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/Fe3O4 nanocomposites on top of the already improved performance of the MXene/Fe3O4 compared with that of pristine MXene. The 2D C/TiO2/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/TiO2/α-Fe nanocomposites makes them promising in the field of electromagnetic wave absorption.