Synergism of 1D CoNi chains anchored 2D reduced graphene oxide with strong interfacial interactions to enhance microwave absorption properties

The reduced graphene oxide (rGO), spherical CoNi/rGO composite and chain-like CoNi/rGO composite were prepared by a facile hydrothermal method at 150 °C for 15 h. Based on the structural information provided by XRD and SEM, we can find that a formation mechanism is associated with the steric-hinerance effect by the surfactant molecules and the magnetic dipole–dipole interaction in the self-assembly process. The microwave absorption properties were also investigated in the 1.0–18.0 GHz frequency range by the vector network analyzer (VNA). The chain-like CoNi/rGO/paraffin composite shows the best microwave absorption properties, and the minimal reflection loss (RL_min) of composite is − 45.95 dB at 9.36 GHz with a thickness of 2.7 mm. The effective absorption (RL < − 10 dB) frequency range could be observed in the frequency of 6.49–6.85 GHz and 8.29–11.88 GHz. The excellent microwave absorption properties of the chain-like CoNi/rGO composite results from the special one-dimensional (1D)/two-dimensional (2D) construction, the multiple polarization and scattering, interfacial polarization and natural resonance. The results show that the chain-like CoNi/rGO composite could be used as a promising electromagnetic wave absorber with characteristics of strong-absorption, wide-band and thin-thickness.