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

• Hierarchical structures of graphene@CoFe2O4@SiO2@TiO2 nanosheets were synthesized.
• The composites have a ferromagnetic behavior.
• The maximum reflection loss of the composites is −62.8 dB at 6.24 GHz.
• The RL value below −10 dB could be obtained in the whole frequency range with the sample thickness varied from 2.0 to 6.0 mm.

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 −62.8 dB at 6.24 GHz with a thickness of 4.9 mm, and the RL value below −10 dB could be obtained in the whole frequency range with the sample thickness varying from 2.0 to 6.0 mm. 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.