Multi-interfacial magnetic carbon nanotubes encapsulated hydrangea-like NiMo/MoC/N-doped carbon composites for efficient microwave absorption

Abstract

Developing high-performance microwave absorbing materials is still a challenge to address the electromagnetic pollution. Interfacial engineering to heighten interfacial polarization plays a key role in microwave absorption. In this work, Multiple interfacial magnetic carbon nanotubes encapsulated hydrangea-like NiMo/MoC/N-doped carbon were prepared via carbothermic reduction. The phase structure and electromagnetic properties can be regulated by thermal treatment temperature. Dielectric loss mechanisms were analyzed deeply by Debye relaxation theory. The results indicated the composites exhibit excellent microwave absorption properties. Reflection loss (RL) less than −20 dB can be achieved in the frequency range of 3.76–17.52 GHz with the absorber thickness varied from 1.3 mm to 5.0 mm when the thermal treatment temperature was 700 °C. The strongest RL value reach to −70.1 dB at 14.2 GHz with the absorber thickness of only 1.52 mm when the thermal treatment temperature is 800 °C. The radar cross section (RCS) reduction calculated through computer simulation technology is used to analyze the microwave absorption capability in the actual far field. The RCS reduction is 17.05 dBm2 when the scattering angle is 0°. This work provided a novel approach for realizing the multi-interface absorbers for high-performance microwave absorption.