Rational design of hierarchical porous Fe3O4/rGO composites with lightweight and high-efficiency microwave absorption

The hierarchical porous flower-like Fe3O4/rGO composites were fabricated through facile microwave-assisted solvothermal method and annealing process. The flower-like Fe3O4 particles were in-situ grown on the rGO. The porous structure led to enhanced multiple reflections and scatterings, facilitating the increased propagation paths and the energy dissipation of electromagnetic wave (EMW). In addition, the construction of hierarchical heterostructure contributed to the strong interfacial polarization and dipole polarization. As a result, the obtained Fe3O4/rGO composites exhibited a minimum reflection loss (RLmin) value of -50.2 dB and a broad effective absorption bandwidth of 4.1 GHz at a matching thickness of only 1.5 mm. Therefore, this work provides a simple and flexible paradigm for the design and synthesis of hierarchical heterostructure as lightweight and high-efficiency EMW absorber.