Reduction synthesis of FexOy@SiO2 core–shell nanostructure with enhanced microwave-absorption properties

•FexOy@SiO2 nanoparticles were kept well-defined in size and shape as Fe3O4@SiO2.•FexOy@SiO2 exhibit enhanced magnetic properties (Ms = 76.032 emu/g).•FexOy@SiO2 exhibit enhanced microwave absorption properties (RL = −23 dB).

Fe3O4@SiO2 core–shell nanostructures with different core diameter and shell thicknesses were prepared by modified stöber method and then converted into FexOy@SiO2 by H2. The structure, morphology and electromagnetic properties of FexOy@SiO2 core–shell nanostructures were investigated. Experimental results demonstrate that the as-prepared FexOy@SiO2 nanoparticles with deeply reduction not only exhibit significantly enhanced magnetic properties with maximum saturation magnetization values of 76.032 emu/g vs. 50.310 emu/g of Fe3O4@SiO2 core–shell spheres, but also show enhanced microwave absorption properties with the maximum reflection loss value of −23 dB at 9.2 GHz under a thickness of 2.5 mm, which give forceful evidences that these FexOy@SiO2 core–shell nanomaterials are attractive materials for microwave absorption applications.

Graphical abstractThe FexOy@SiO2 nanoparticles were kept well-defined in size and shape as the same with the Fe3O4@SiO2 core–shell nanoparticles completely. The results also show that FexOy@SiO2 core–shell nanoparticles have significantly enhanced microwave absorption properties with the maximum reflection loss value of −23 dB at 9.2 GHz with a thickness of 2.5 mm.Figure optionsDownload full-size imageDownload as PowerPoint slide