Bimetallic MOFs/MXene derived CoNi@C@Ti₃C₂T_x/TiO₂ nanocomposites for high-efficiency electromagnetic wave absorption

Constructing intricately designed multiple heterogeneous interfaces offers an effective strategy for exploring lightweight and efficient microwave absorbing materials (MAMs). Herein, the CoNi@C@Ti3C2Tx/TiO2 (CNCTT) nanocomposites with multiple heterogeneous interfaces were synthesized using the straightforward solvothermal method, electrostatic self-assembly, and subsequent heat treatment process, utilizing bimetallic CoNi-MOF-74@few-layered Ti3C2Tx MXene as the precursor. The modulation of composition, microstructure, and electro-magnetic wave absorption (EMWA) properties of the CNCTT nanocomposites was comprehensively investigated by simply controlling the ratio of magnetic metal sources. Hierarchical porous structure simultaneously promotes interfacial polarization by quaternary CoNi/C/MXene/TiO2 interfaces, enhances magnetic loss by the CoNi nanoparticles coupling network, enlarges conduction loss by the graphite carbon layer/MXene/TiO2 triple-network, and optimizes impedance matching with the synergistic effect of dielectric loss and magnetic loss. Significantly, it is observed that the C3N3CTT nanocomposite, with the molar ratio of Co:Ni is 3:3 and a filler loading of 30 wt%, demonstrates an impressive minimum reflection loss (RLmin) of-70.26 dB at 15.92 GHz and an effective absorbing bandwidth (EAB, RL <-10 dB) of 4.19 GHz with an absorption layer thickness of 1.7 mm. Furthermore, the RLmin remains notable-40.50 dB with an expanded EAB of 5.17 GHz at a thickness of 1.8 mm. This endeavor can provide significant insights into the potential applications of MOF-derived composites in the realm of efficient electromagnetic wave absorption.