In situ growth of 1D carbon nanotubes on well-designed 2D Ni/N co-decorated carbon sheets toward excellent electromagnetic wave absorbers

Abstract Rational construction of complex hierarchical structure with dielectric/magnetic components is an effective strategy to achieve outstanding electromagnetic wave (EMW) absorbers. In this work, Ni/N-doped two-dimensional carbon sheets (Ni-NC) were subtly prepared through a facile coordination-exfoliation process based on a bulk precursor ethylenediaminetetraacetic acid-nickel (EDTA-Ni). Subsequently, carbon nanotubes (CNTs) were catalytically grown in situ on the surface of the carbon sheet to fabricate a series of forest-like three-dimensional (3D) structured composites (Ni-NC/CNTs) which combine multiple advantages of well-dispersed Ni particles, massive interfacial polarization and rich air contact within the skeleton. The composites exhibit different EMW attenuation capabilities by tuning impedance matching, interfacial polarization, dipole polarization, 3D conductive loss and magnetic loss that manipulated by changing the calcination temperature. Amongst them, Ni-NC/CNTs(7 0 0) has a strong absorption capacity in the X-band region, where the minimum reflection loss can reach −55.3 dB at 8.72 GHz with the thickness of 2.7 mm. More extraordinarily, this composite material exhibits an effective absorption bandwidth of 14.32 GHz by adjusting the thickness from 1.5 mm to 5.0 mm. This work provides a simple design and feasible synthesis strategy for light EMW absorber with wide band and strong absorption.