Two-dimensional porous few-layer MXene-derived bimetallic CoNi@Ti3C2Tx/CNT/TiO2 nanocomposites for ultrathin high-performance electromagnetic wave absorbers

The development of electromagnetic wave-absorbing materials has attracted much attention in recent years, as the broad application of electronic devices in communication and military radar operations has brought about serious problems such as electromagnetic pollution and interference. In this study, a bimetallic MOF/MXene based electromagnetic nanocomposite CoNi@Ti 3 C 2 T x /CNT/TiO 2 (CNTCT) is developed. The composite system with multiple heterogeneous interfaces is successfully constructed by constructing a porous few-layer MXene substrate through the H 2 O 2 etching technique, combined with electrostatic self-assembly of CoNi-MOF-74 and a high-temperature annealing process. The porous MXene provides high surface area and defect sites, the CNT/TiO 2 hetero-interface generated by pyrolytic reduction effectively promotes the multi-polarization mechanism, and the magnetic CoNi component significantly enhances the magnetic loss performance through the natural/exchange resonance and eddy current loss to realize the high-performance broadband electromagnetic wave absorption. CNTCT-3 composites obtained −73.82   dB RL min at 9.74   GHz (matched thickness of 2.53   mm) and 3.79   GHz EAB; when the thickness was reduced to 1.93   mm, the EAB was expanded to 5.65   GHz. This work provides insights into potential applications of novel MXene-derived composites in electromagnetic wave absorption through dielectric-magnetic synergistic effects and structural modulation applications.