Novel hierarchical RGO/MoS2/K-αMnO2 composite architectures with enhanced broadband microwave absorption performance
Here we report the successful preparation of hierarchical structures of reduced graphene oxide/molybdenum disulfide/potassium-alpha manganese dioxide (RGO/MoS2/K-αMnO2) composites via an improved hydrothermal method. The obtained composites display unique ternary architectures in which uniform K-αMnO2 nanospheres as antennas are distributed on the surface of RGO/MoS2 composites. The minimum reflection losses (RL) of MoS2, RGO/MoS2 and RGO/MoS2/K-αMnO2 in the frequency of 2.0–18.0 GHz are −7.8 dB, −21.7 dB and −71.7 dB with a thickness of 8.0 mm, 1.8 mm and 3.8 mm, respectively. Moreover, the RL values of RGO/MoS2/K-αMnO2 composites exceeding −20 dB have been achieved in broad frequency bands of 2.5–18.0 GHz. The addition of K-αMnO2 adjusts the balance between εr and μr of the composites, resulting in a larger α value and a higher matching impedance ratio. The excellent microwave absorption performance of the ternary composites mainly originates from a particular hierarchical antenna-like structure, good impedance matching, polarization relaxation, and the efficient complementarities between RGO/MoS2 and K-αMnO2. Finally, this RGO/MoS2/K-αMnO2 composite with strong absorption and wide frequency will be a promising material in the field of microwave absorption.