A facile synthesis of core-shell Fe3O4@C(N) composites and their microwave absorption properties

The core-shell Fe3O4@C(N) composites with a Fe3O4 core surrounded by an N-doped C shell have been successfully fabricated via a dopamine (DA) self-polymerization process around Fe3O4 and sequential heat-treatment processes. The electromagnetic parameters can be effectively regulated by the DA usage. The sample prepared with 2 mM DA shows the optimal reflection loss (RL) of - 45 dB at a matching thickness of 3.6 mm and the bandwidth with RL < - 10 dB cover 14.7 GHz with the integrated thickness of 2-6 mm. The excellent microwave absorption performance can be mainly attributed to effective complementary between magnetic loss and dielectric loss originated from multiple magnetic resonance and eddy current loss from Fe3O4 core, dipolar polarization and conduction loss in C(N) shell and interfacial polarization at core-shell interface, achieving the preferable electromagnetic impedance match and microwave attenuation.

Automated summary

Core-shell Fe3O4@C(N) composites with Fe3O4 core and N-doped C shell were successfully synthesized through dopamine (DA) self-polymerization and heat treatment, showing excellent microwave absorption performance due to effective complementary between magnetic loss and dielectric loss.