The one-pot syntheses of Fe@(C, N) nanocapsules for electromagnetic absorption at gigahertz

Fe@(C, N) nanocapsules with Fe nanoparticles as the core and N-doped onion-like carbon as the shell are synthesized by the arc-discharge method. The complex permittivity, dielectric loss and microwave absorption properties of the Fe@(C, N) nanocapsules are improved by the doping of N. Compared with Fe@C nanocapsules, Fe@(C, N) nanocapsules exhibit the thinner thickness for the same effective absorbing band width, and the absorption peaks of the Fe@(C, N) nanocapsules at the same thickness shift to a lower frequency, ascribed to the large amount of defects from the doping of N.