Three dimensional graphene-supported nitrogen-doped carbon nanotube architectures for attenuation of electromagnetic energy

In this work, we use a metal-organic framework and layered double hydroxide nanosheets as precursors to grow transition-metal nanoparticle-encapsulated nitrogen-doped carbon nanotubes on ultrathin graphene sheets. The as-fabricated samples exhibit three-dimensional structures with high electrical conductivities, abundant defects, multiple interfaces and nitrogen dopants. As applied for the attenuation of electromagnetic energy, the optimized 3D architecture with CoNi bimetal nanoparticles exhibits excellent attenuation properties of electromagnetic energy even at a thin thickness of 1.5 mm and a low filling ratio of 10 wt% in a paraffin matrix, superior to those of single-metal based 3D architectures and most reported materials. The experimental results demonstrate that the dielectric loss and the impedance matching characteristic can be modulated by adjusting metal compositions, which are responsible for the difference of the 3D architectures in EME attenuation properties. Our strategy opens a new way for lightweight materials for the attenuation of electromagnetic energy.