Tuning the shell thickness of core-shell α-Fe2O3@SiO2 nanoparticles to promote microwave absorption

Various advanced microwave absorbing materials have been developed for reducing/avoiding the harm of microwave radiation. Among them, core-shell structural nanomaterials have been widely fabricated for microwave absorption. However, the structure-performance relationship between shell thickness and microwave absorption performance is rarely reported. In this paper, we first explored the structure-performance relationship between shell thickness and microwave absorption performance, based on the core-shell alpha-Fe2O3@SiO2 nanoparticles with a constant alpha-Fe2O3-core size and changeable SiO2-shell thickness. With increasing the SiO2-shell thickness, the microwave absorption ability first increased, then decreased. Under a proper SiO2-shell thickness of 35 nm, alpha-Fe2O3@SiO2 sample achieved the strongest microwave absorbing ability with a reflection loss minimum value of -4.3 dB, better than that of pure alpha-Fe2O3 (-3.8 dB). This enhanced microwave absorption performance was mainly derived from the dielectric loss. Although the absolute value of the reflection loss was relatively low (-4.3 dB), this study shed an important reference on designing next-generation advanced iron oxide-based materials for microwave absorption. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

This study investigated the relationship between shell thickness and microwave absorption performance in core-shell nanoparticles. The findings showed that the sample with an optimal shell thickness achieved the strongest microwave absorption ability. This research provides important insights for designing next-generation advanced iron oxide-based materials for microwave absorption.