Achieving effective broadband microwave absorption with Fe3O4@C supraparticles

The X band (8 GHz–12 GHz) is the electromagnetic wave band emitted by most electronic instruments in our life, which will cause electromagnetic pollution harm to human health. Due to the coexistence of magnetic loss and dielectric loss, the modified Fe3O4-carbon-based nanomaterial exhibit strong electromagnetic (EM) wave absorptive capacity. However, there is a problem that the effective absorption bandwidth (EAB, the frequency bandwidth of reflection loss is less than −10 dB) of the X band is narrow. Increasing the EAB value of Fe3O4-carbon-based materials is of great significance for reducing electromagnetic pollution. Here, an emulsion-based self-assembly technique and ligand carbonization treatment have been used to construct the Fe3O4@C supraparticles for the evaluation of EM performance. The Fe3O4@C supraparticles exhibit excellent EM absorption properties, which can achieve full coverage of X band from 6.52 GHz to 12.9 GHz at a sample thickness of 3 mm. Besides, the optimum EAB value of Fe3O4@C supraparticles is up to 8.55 GHz from 9 to 18 GHz at a sample thickness of 2.5 mm. The Fe3O4@C supraparticles with superlattice structure will have potential development prospects in the application of broadband absorption.