Synthesis, characterization and enhanced electromagnetic properties of NiFe2O4@SiO2-decorated reduced graphene oxide nanosheets

• Published in: Ceramics international 2016-11, Vol.42 (15), p.17374-17381
• Main Authors: Wang, Yan, Zhang, Wenzhi, Luo, Chunyan, Wu, Xinming, Wang, Qiguan, Chen, Weixing, Li, Jinhua
• Format: Article
• Language: English
• Subjects: Core-shell structure; Graphene; Microwave absorption; Nanocomposites
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2016.08.036

A ternary composite of NiFe2O4@SiO2@RGO was synthesized using a three-step method. A facile hydrothermal route (NiFe2O4)was used in the first step, and the modified Sto¨ber method (NiFeO4@SiO2)in second step, followed by reduced reaction of GO using a hydrothermal reaction (NiFe2O4@SiO2@RGO). The obtained samples were characterized by various instruments and The TEM analysis indicated that NiFe2O4particles were homogenously enwrapped by SiO2. The NiFe2O4particles with a size of about 10–15nm are core, SiO2forms shell and the core-shell structured NiFe2O4@SiO2disperses on the surface of RGO. The ternary composite shows the best microwave absorption properties (−42.9dB), which is higher than NiFe2O4(−11.3dB)and NiFe2O4@SiO2(−25.9dB). This is mainly attributed to the synergistic effects between permittivity and permeability and enhanced effects at the interfaces. For the NiFe2O4@SiO2@RGO composite, the maximum reflection loss can reach −42.9dB at 12.2GHz and the absorption bandwidth with the reflection loss below −10dB is 6.2GHz(from 10.1to 16.3GHz)for a thickness of 3mm. Our results indicate that the core-shell structured NiFe2O4@SiO2 on graphene is a promising microwave absorbent with thin thickness, light weight, strong absorption, and broad bandwidth.