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Intercalating Hybrids of Sandwich-like Fe₃O₄–Graphite: Synthesis and Their Synergistic Enhancement of Microwave Absorption

Peng, Fuxi, Meng, Fanbin, Guo, Yifan, Wang, Huagao, Huang, Fei, Zhou, Zuowan
ACS sustainable chemistry & engineering 2018 v.6 no.12 pp. 16744-16753
absorption, electromagnetic radiation, ferric chloride, graphene, iron oxides, magnetism, microstructure, nanoparticles, pollution control, synergism, temperature
Rational design on the components and microstructures of microwave-absorbing materials can pave the way for upgrading their performances in electromagnetic pollution prevention. In this study, Fe₃O₄–graphite intercalation hybrids (Fe₃O₄-GIH) with unique sandwich-like microstructure are fabricated by a molten salt route and subsequent temperature reduction. It is found that the gaseous FeCl₃ molecules at high temperature can diffuse into the graphite interlayer plane to obtain FeCl₃-GIH, and the intercalated FeCl₃ is then transferred into Fe₃O₄ nanoparticles under high temperature reduction, which can prop open the graphite interlayer, thus achieving sandwich-like Fe₃O₄-GIH. Therefore, one-step synthesis can give perfect features, such as transformation of graphite into graphene sheets, introduction of a magnetic component, and construction of multiple interfaces, which are a benefit to the microwave absorption (MA). As a result, the maximum reflection loss of the as-obtained Fe₃O₄-GIH can be up to −51 dB at 4.3 GHz with a matching thickness of 4.8 mm. Furthermore, the MA performances can be tuned by regulating the interlayer spacing of Fe₃O₄-GIH. The excellent microwave absorption performance may attribute to the synergistic effect between Fe₃O₄ nanoparticles with magnetic loss, graphite with dielectric loss, and novel interfacial polarization originating from the sandwich-like Fe₃O₄-GIH. Additionally, it can be supposed that these sandwich structures are more beneficial for scattering the incident electromagnetic wave due to their large spacing and porous features.