Controllable synthesis and enhanced microwave absorption properities of novel lightweight graphene quantum dots/hexagonal boron nitride composites

Here we report the successful preparation of hexagonal boron nitride nanosheets supported graphene quantum dots (GQDs/BNNs) composites by one-step hydrothermal method. For the first time, GQDs was used as an absorbent for microwave absorbing materials. In this work, the relationship between the concentration of GQDs in GQDs/BNNs composites and the microwave absorption performance was discussed. As an efficient wave absorber, GQDs/BNNs had excellent microwave absorption properties. In the frequency bands of 2–18 GHz, minimum reflection loss (RLmin) of GQDs/BNNs can reach as low as −59.9 dB at 2.8 mm. Significantly, effective bandwidth of RL values exceeding −10 dB was about 35 GHz, resulting in covering almost entire measured bandwidth. Furthermore, BNNs with high stability, thermal conductivity and hydrophobicity can greatly enhance the overall performance of GQDs/BNNs. Finally, GQDs/BNNs composites with strong absorption and wide frequency will be a novel promising absorbent in the field of microwave absorption.