Facile synthesis of highly conductive MoS₂/graphene nanohybrids with hetero-structures as excellent microwave absorbers

Two-dimensional (2D) MoS₂/graphene nanosheet (MoS₂/GN) hybrids have been demonstrated to be promising microwave absorption (MA) materials due to their unique chemical and physical properties as well as rich impedance matching. However, the reported strategies for preparing MoS₂/GN hybrids have limited their application potential due to the complex, high-cost and inefficient preparation processes. On the other hand, it is of note that the main source of graphene is based on converting insulating graphene oxides (GO) back to conductive reduced graphene oxides (RGO). Thus, the MA performance of obtained MoS₂/RGO nanohybrids is greatly affected by the conversion process of GO. In this work, we prepared the MoS₂/GN hybrids by a facile hydrothermal method with directly introducing highly pure and electroconductive GNs. It is found that the highest reflection loss value of the sample-wax containing 40% MoS₂/GN is −57.31 dB at a thickness of 2.58 mm, and the bandwidth of RL values less than −10 dB can reach up to 12.28 GHz (from 5.72 to 18 GHz) when an appropriate absorber thickness between 1.5 and 4 mm is chosen. The excellent MA performances emanate from effective conjugation of MoS₂ with GN (Mo-C bond between the interfaces), which provides the dielectric loss caused by multi-relaxation, conductance, and polarization. Taking into account the facile synthesis route and their excellent MA performance, the MoS₂/GNs hybrid nanosheets and those composite materials with similar isomorphic hetero-structures are very promising for a wide range of MA applications.