Hierarchical structures of graphene@CoFe2O4@SiO2@TiO2 nanosheets:Synthesis and excellent microwave absorption properties

Hierarchical structures of graphene@CoFe₂O₄@SiO₂@TiO₂ nanosheets were successfully synthesized by combining the versatile sol–gel process with a hydrothermal reaction. Scanning electron microscopy and transmission electron microscopy observations display that the TiO₂ nanosheets are mostly grown upright on the top of graphene@CoFe₂O₄@SiO₂ support with a random orientation. When its microwave absorbing properties were investigated, the results show that the maximum reflection loss of the composites is up to ‑62.8dB at 6.24GHz with a thickness of 4.9mm, and the R_L value below ‑10dB could be obtained in the whole frequency range with the sample thickness varying from 2.0 to 6.0mm. The excellent microwave absorption properties of graphene@CoFe₂O₄@SiO₂@TiO₂ nanosheets can be used as an attractive candidate for new type of microwave absorption materials.