In-situ synthesis of carbon nanotubes decorated by magnetite nanoclusters and their applications as highly efficient and enhanced microwave absorber

Abstract We report a facile, in-situ polyol approach for the fabrication of magnetite/multi-wall carbon nanotubes (Fe 3 O 4 /MWCNTs) hybrids as highly efficient microwave absorber. SEM, TEM and XPS technologies indicate that uniform Fe 3 O 4 nanoclusters were chemically bonded and anchored on the surface of MWCNTs without aggregation. ESR result suggests that the dipolar interactions of magnetic Fe 3 O 4 nanoclusters were enhanced in the Fe 3 O 4 /MWCNTs hybrids. Combining the synergistic benefits of magnetic Fe 3 O 4 nanoclusters and electric lightweight MWCNTs, the Fe 3 O 4 /MWCNTs hybrids perform highly improved microwave absorption properties in comparison with pure Fe 3 O 4 nanoclusters and MWCNTs. For Fe 3 O 4 /MWCNTs hybrids, the strongest reflection loss (RL) values can reach −60.7 dB at 11 GHz with a matching thickness of only 1.8 mm, and the effective microwave absorption bandwidth (RL>−10 dB) ranges from 3.0 GHz to 15.6 GHz when the thickness is 1.5–5.0 mm. Whereas, the RL value for the pure Fe 3 O 4 nanoclusters and MWCNTs cannot reach −10 dB in the whole measured frequency. These results suggest that the synergistic effect of the Fe 3 O 4 /MWCNTs hybrids has a great influence on the extremely enhanced microwave absorption properties. Taking the advantages of lightweight, antioxidation, high-efficient, easy preparation and low-cost, the Fe 3 O 4 /MWCNTs hybrids is believed to be a good candidate for microwave absorption, especially in the X-band (8–12 GHz).