Covalent bonding-designed Ti3C2Tx@Fe3O4@SiO2 nanocomposites for high-efficiency microwave absorption

Construction of homogeneous composite structures based on covalent bond mediation represents an effective approach to achieve excellent microwave absorption performance (MAP). In this study, Ti 3 C 2 T x @Fe 3 O 4 @SiO 2 nanocomposites with uniform architecture were successfully fabricated using 3-aminopropyltrimethoxysilane (APTMS) as a coupling agent. By functionalizing Fe 3 O 4 @SiO 2 nanoparticles with surface amino groups via APTMS, covalent bonding was established between Ti 3 C 2 T x nanosheets through amide linkages, enabling homogeneous anchoring of Fe 3 O 4 @SiO 2 within Ti 3 C 2 T x . This fabrication method based on covalent bond mediation enhances interfacial polarization of the composite while simultaneously optimizing its conductive networks and impedance matching characteristics. Together with intrinsic magnetic resonance and eddy current loss mechanisms of Fe 3 O 4 , these enhancements endow the Ti 3 C 2 T x @Fe 3 O 4 @SiO 2 composites with exceptional MAP. At a thickness of 1.26 mm, the material exhibits an effective absorption bandwidth of 4.11 GHz, spanning the frequency range of the Ku band. At a slightly higher thickness (1.5 mm), a minimum reflection loss of −48.98 dB is attained. Notably, the composites also demonstrate superior thermal conductivity, enabling efficient electromagnetic energy dissipation through the conversion into thermal energy. The proposed covalent bonding-based scheme provides a theoretical framework for microstructure design and performance optimization of novel MXene-based microwave absorbers.