MoS nanoparticle/activated carbon composite as a dual-band material for absorbing microwaves.

In the search for novel high-performance microwave (MW) absorbers, MoS has shown promise as a MW-absorbing material, but its poor impedance matching limits its applications. Herein, a facile hydrothermal method was used to produce a composite consisting of activated carbon (AC) derived from waste biomass and -grown MoS nanoparticles. Its microwave absorption properties were examined in the 2-18 GHz frequency range, and FESEM and HRTEM images confirmed the formation of MoS nanoparticles on the AC. The maximum reflection loss (RL) for the MoS/AC composite was -31.8 dB (@16.72 GHz) at 20 wt% filler loading. At 50 wt% filler loading, the MoS/AC (MAC50) composite exhibited unique dual-band absorption characteristics in the C and K bands. An effective absorption bandwidth (RL < -10 dB) of 10.4 GHz (3-5.2 GHz, 9.8-18 GHz) was achieved at various thicknesses that covered the entire K band. Therefore, a sole dielectric absorber can easily be tuned to absorb MWs at multiple frequency ranges. The large surface area and conduction losses of AC combined with the superior dielectric loss properties of MoS resulted in improved impedance matching and attenuation ability of the MoS/AC composite. Thus, MoS/AC is a promising low-cost dielectric absorber for MW absorption applications.