Nitrogen-doped carbon nanosheets containing Fe3C nanoparticles encapsulated in nitrogen-doped graphene shells for high-performance electromagnetic wave absorbing materials

Nitrogen-doped carbon sheets containing Fe3C nanoparticles encapsulated in nitrogen-doped graphene shells are fabricated through heating the mixture of urea and ferric acetylacetonate and the subsequent treatment in hot acid solution. The nitrogen-doped carbon sheets have a lateral length ranging from hundred nanometers to several micrometers, while the Fe3C nanoparticles encapsulated in nitrogen-doped graphene have a diameter of approximately 60 nm. The nitrogen-doped carbon sheets exhibit excellent electromagnetic wave absorption property. Typically, the optimal sample has the effective absorption bandwidth of 6.0 GHz at the absorber thicknesses of only 2.0 mm, favorably comparable to those of the magnetic absorbers reported previously. The excellent electromagnetic wave absorption property of nitrogen-doped carbon sheets containing Fe3C nanocapsules encapsulated in the nitrogen-doped graphene shells can be explained by their better impedance matching character and enhanced dielectric loss. (C) 2018 Elsevier Ltd. All rights reserved.