Tunable and improved microwave absorption of flower-like core@shell MFe2O4 @MoS2 ( M = Mn, Ni and Zn) nanocomposites by defect and interface engineering

Previous results revealed that the defect and/or interface had a great impact on the electromagnetic pa-rameters of materials. In order to understand the main physical mechanisms and effectively utilize these strategies, in this study, MFe2O4 and flower-like core@shell MFe2O4 @MoS2 ( M = Mn, Ni, and Zn) sam-ples with different categories were elaborately designed and selectively produced in large scale through a simple two-step hydrothermal reaction. We conducted the systematical investigation on their microstruc-tures, electromagnetic parameters and microwave absorption performances (MAPs). The obtained results revealed that the large radius of M 2 + cation could effectively boost the concentration of oxygen vacancy in the MFe2O4 and MFe2O4 @MoS2 samples, which resulted in the improvement of dielectric loss capabil-ities and MAPs. Furthermore, the introduction of MoS2 nanosheets greatly improved the interfacial effect and enhanced the polarization loss capabilities, which also boosted the MAPs. By taking full advantage of the defect and interface, the designed MFe2O4 @MoS2 samples displayed tunable and excellent com-prehensive MAPs including strong absorption capability, wide absorption bandwidth and thin matching thicknesses. Therefore, the clear understanding of defect and interface engineering made these strategies well elaborately designed and applicable to improving MAPs.(c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this study, MFe2O4 and MFe2O4 @MoS2 samples with different categories were elaborately designed and selectively produced. The investigation revealed that the large radius of M2+ cation effectively boosted the concentration of oxygen vacancy in the samples, improving the dielectric loss capabilities and microwave absorption performances. The introduction of MoS2 nanosheets enhanced the interfacial effect and polarization loss capabilities, further boosting the microwave absorption performances. The designed MFe2O4 @MoS2 samples displayed tunable and excellent comprehensive microwave absorption performances.