Construction of dual heterogeneous interface between zigzag-like Mo–MXene nanofibers and small CoNi@NC nanoparticles for electromagnetic wave absorption

Two-dimensional (2D) transition metal carbides (MXene) process attractive conductivity and abundant surface functional groups, providing immense potential in the field of electromagnetic wave (EMW) absorption. However, the high conductivity and spontaneous aggregation of MXene suffer from limited EMW response. Inspired by the dielectric-magnetic synergy effect, the strategy of decorating MXene with magnetic elements is expected to solve this challenge. In this work, zigzag-like Mo₂TiC₂ MXene nanofiber (Mo-MXene NFs) cross-linked networks are fabricated using HF etching and KOH shearing processes. Subsequently, Co-MOF and derived CoNi LDH ultrathin nanosheets are grown inside Mo-MXene NFs, and the N-doped carbon matrix anchored by CoNi alloy nanoparticles formed by pyrolysis is firmly embedded in the Mo-MXene NFs network. Benefiting from the synergistic effect of highly dispersed small CoNi alloy nanoparticles, a 3D conductive network assembled by zigzag-like Mo-MXene NFs, numerous N-doped hollow carbon vesicles, and abundant dual heterogeneous interface, the designed Mo-MXene/CoNi-NC heterostructure provides robust EMW absorption ability with a reflection loss (R_L) value of -68.45 dB at a matching thickness of 4.38 mm. The robust EMW absorption performance can be attributed to the excellent dielectric losses, magnetic loss, impedance matching, and multiple scattering and reflection triggered by the unique 3D network structure. This work puts up great potential in developing advanced MXene-based EMW absorption devices.