Hollow ZnO/Fe3O4@C Nanofibers for Efficient Electromagnetic Wave Absorption

A type of hollow core–shell ZnO/Fe3O4@C fibers were fabricated by a facile combination of electrospinning, calcination, and pyrolytic pyrrole-derived carbon coating. The combination of ZnO/Fe3O4 fibers and carbon nanolayer improved the dielectric loss capability of the nanocomposites and obtained good impedance matching, leading to excellent electromagnetic wave (EMW) absorption performance. The minimum reflection loss of the ZnO/Fe3O4@C nanocomposites reached −74.2 dB at a thickness of merely 2.2 mm, and the effective absorption bandwidth reached 5.5 GHz at a matching thickness of 2.1 mm. Compared with the ZnO- or Fe3O4-based composites ever reported, our ZnO/Fe3O4@C nanocomposites exhibited superior EMW absorption characteristics due to the efficient design of multiple synergistical components and hollow fibrous structures. Combined with the facile, scalable preparation approach, the hollow core–shell ZnO/Fe3O4@C nanocomposite fibers with high EMW absorption performance show great potential for EMW absorption applications.