Electromagnetic wave absorption of fabricated Fe/Fe3O4/C hollow fibers derived from ceiba fiber templates

Electromagnetic-wave-absorbing fibers have been proposed as a method for addressing electromagnetic wave pollution. In this study, Fe/Fe3O4/C hollow electromagnetic wave absorbers were prepared using hollow ceiba fibers as templates. The ceiba fibers were immersed in an Fe(NO3)3 solution and sintered in argon to obtain Fe/C or Fe3O4/C hollow fibers with biochar. The wave absorption performance of the proposed Fe/Fe3O4/C hollow fibers was generally better than that of standard solid fibers. A minimum reflection loss of -40.1 dB and an optimal effective bandwidth of 3.26 GHz were obtained. The proposed hollow structure could make the incident electromagnetic waves reflect and scatter many times, which led to significant electromagnetic wave energy consumption. Moreover, the impedance matching of magnetic materials, such as iron and its oxides, could be adjusted using the biochar of ceiba so that magnetic and dielectric losses work together to absorb electromag-netic waves.