Nature of Electromagnetic-Transparent SiO2 Shell in Hybrid Nanostructure Enhancing Electromagnetic Attenuation

The understanding of the structure activity relationship can help us design desired functional materials. SiO2 shell is widely used as a physicochemical inert layer to protect materials from corrosion or oxidization. But, in electromagnetic (EM) absorption studies, silica shell, supposed to be EM transparent, has been found to significantly influence the EM absorption performance. Here, we studied the microstructure, EM parameters, and electronic structure of silica shell coated SiC/Co (SiC/Co@SiO2) nanowires to figure out the nature of silica shell influencing on their EM absorption. Xray absorption near-edge structures on Co L3,2-edge and O K-edge analysis confirm that silica links with Co by Si-O-Co bonds. Electron transfer takes place between silica and Co, which leads to formation of gradient e field within silica and more incident EM wave entering into the absorbers. Generating significant interfacial polarization, the silica shell improves the EM absorption performance. The present research offers a novel insight on the functional role of silica shell.