Controllable synthesis of 3D porous MXene/polypyrrole/Fe3O4 with magnetically tunable pore structures for electromagnetic wave absorption

With the rapid advancement of digital and communication technologies, electromagnetic pollution poses an increasingly serious threat to the environment and precision instruments. In this study we report a three-dimensional MXene/PPy/Fe₃O₄(3D MPF) composite with an ordered three-dimensional network structure constructed by an in-situ self-assembly method. The porous structure of 3D MPF was adjusted to induce the assembly of MXene nanosheets through different EDA additions. The 3D MPF exhibits cross-linked and interpenetrating conductive networks that facilitate efficient electron transfer and reflection. The multi-layer heterogeneous interfaces and functional groups of the 3D MPF generate more polarization defects, causing significant reflection and scattering of incident electromagnetic waves. Moreover, the inclusion of Fe₃O₄ supports magnetic loss and optimizes the impedance matching of the 3D MPF. The 3D MPF exhibits a maximum reflection loss of −55.21 dB at a thickness of 3.31 mm when the ratio of MXene to Fe₃O₄ is 1:1. At a thickness of 1.41 mm, the effective absorption bandwidth reaches 3.44 GHz (from 13.84 GHz to 17.28 GHz). By adjusting the matching thickness, the effective absorption bandwidth of the 3D MPF ranges from 3.44 GHz to 18 GHz, with reflection losses below −10 dB, indicating its significant potential in electromagnetic wave absorption.