Rational Construction of Ti₃C₂Tx/Co-MOF-Derived Laminated Co/TiO₂-C Hybrids for Enhanced Electromagnetic Wave Absorption

Lightweight and compatible metal–organic framework (MOF)-derived carbon-based composites are widely used in electromagnetic (EM) absorption. Their combination with laminated TiO 2 -C (derived from Ti 3 C 2 T x ) is expected to further strengthen the EM attenuation ability. Herein, novel laminated Co/TiO 2 -C hybrids were derived from Ti 3 C 2 T x /Co-MOF using heat treatment. Compared with pristine MOF-derived carbon-based composites, the EM absorption ability of Co/TiO 2 -C was improved by multiple reflections between multilayered microstructures and the improved polarization loss (due to the heterogeneous interfaces, residual defects, and dipole polarization) and the strengthened conductivity loss caused by the carbon layers. Specifically, for the Co/TiO 2 -C hybrids at thicknesses of 3.0 and 2.0 mm, the optimal reflection loss (RL) was −41.1 dB at 9.0 GHz and −31.0 dB at 13.9 GHz, with effective bandwidths (RL ≤ −10 dB) of 3.04 and 4.04 GHz, respectively. This study will underline the preparation of carbon-based absorbing materials starting from MXene/MOF hybrids.