Biomass-derived graphene-like porous carbon nanosheets towards ultralight microwave absorption and excellent thermal infrared properties

Searching for ultralight microwave absorber with good heat-insulating property is highly desirable to fulfill the technical requirement of modern society. Herein, the two-dimension (2D) graphene-like porous carbon nanosheets (GPCN) derived from the waste pomelo peel were developed. The preparation is performed by a facile hydrothermal process with synergistic usage of HAc and H2O2. Interestingly, the thickness and porosity of GPCN can be readily regulated by adjusting addition amount of the reagents. The related synthetic mechanism is investigated in depth. Compared with traditional graphene, the fabrication strategy of GPCN possesses many advantages, such as low cost, high yield and ease of production. The results show that GPCN presents superior thermal insulation and microwave absorption properties. The heat-insulating property is comparable to commercial products, e.g. polyurethanes (PU), nickel foam (NF), carbon foam (CF). The strong microwave absorption intensity of −56.4 dB and bandwidth of 6.4 GHz is achieved under ultralow filling ratio of 4 wt%. Moreover, the density of assembled 3D macroscopically product is merely 0.01 g/cm−3. The excellent performance should be attributed to the unique 2D morphology and high porosity of GPCN. Our work paves a new way for developing porous carbon nanosheet from sustainable biomass as heat-insulating ultralight microwave absorber.