In-situ construction of CNTs/laterite composites for enhanced microwave absorption

Carbon nanotubes have the significant disadvantage of insufficient magnetic loss as a microwave absorbing material, while transition metal catalysts for the preparation of carbon nanotubes still limit the cost reduction. In this study, a facile in-situ strategy was developed to synthesize CNTs/laterite composites, smartly employing the catalysts performance of laterite to realize the synthesis of CNTs and simultaneously construct three-dimensional (3D) “caterpillar” structure. As expected, the exposed CNTs with high crystallinity in caterpillar-like CNTs/laterite composites are believed to provide a good conductive 3D network and abundant paths for trapping of incident electromagnetic waves, as well as the iron nanoparticles produced by hydrogen reduction during the in-situ catalytic growth of carbon nanotubes on laterite significantly increase the magnetism of the materials and thus increase the magnetic loss. As a result, the RL curves of the CNTs/laterite-paraffin composites show a maximum reflection loss of −77 dB at 3.2 GHz with 4 mm thickness. Generally, this synthesis strategy presented in this study paves a new way for the fabrication of low-cost CNTs-based composite with high performance for microwave absorbing.