Interface engineering in the hierarchical assembly of carbon-confined Fe3O4 nanospheres for enhanced microwave absorption. Issue 16 (25th March 2022)

• Record Type: Journal Article
• Authors: Shi, Xiaofeng; Wu, Zhengchen; Liu, Zhengwang; Lv, Jianguo; Zi, Zhenfa; Che, Renchao
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 16(2022)
• Page Start: 8807
• Page End: 8816
• Publication Date: 2022-03-25
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta11005e
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The strong magnetic coupling effect and intensive interfacial polarization endow hierarchical core–shell Fe3 O4 @C composites with excellent microwave absorption performance. Abstract : Heterointerfaces can induce dielectric polarization relaxation to remarkably boost microwave absorption performance. However, delicately engineering a homogeneous magnetic–dielectric heterostructure remains a considerable challenge. Herein, novel hierarchical Fe3 O4 @C microspheres have been successfully fabricated via polydopamine confinement and sequential calcination. In the product, each primary nanoparticle (Fe3 O4 microsphere) is confined within a thin layer of carbon, constructing a multi-interface heterostructure. Interface engineering in such a hierarchical assembly of Fe3 O4 @C core–shell nanoparticles results in unique performance superiority in terms of microwave absorption compared with traditional carbon-coated Fe3 O4 microspheres. The maximum reflection loss value reaches −55.4 dB, and the broad effective absorption bandwidth covers a range as wide as 9.5 GHz (8.5–18 GHz) at only 2.0 mm. Importantly, the confinement effect simultaneously results in strong magnetic coupling interactions and a well-defined charge distribution at the contacted interfaces, which ultimately enhance the magnetic loss and dielectric loss, respectively. Besides, the dielectric carbon shell with optimized thickness facilitates the spread of the magnetic flux line, leading to intensive magnetic–dielectric synergy as well as matched impedance. These results might provide a new insight into the preparation of highly efficient microwave absorbers by optimal microstructure engineering.