Cellular-like sericin-derived carbon decorated reduced graphene oxide for tunable microwave absorption

Sodium hydroxide (NaOH) activation on biomass-derived carbon materials has been a developed strategy to construct the porous and lightweight microwave absorber. However, the resulting random porous structures still remain a formidable challenge to optimize the impedance matching and microwave absorption performance. Here, a sericin-guided NaOH activation and subsequent carbonization process were proposed to synthesize uniform cellular-like sericin-derived carbon decorated reduced graphene oxide (SC/rGO) nanohybrids. The NaOH was used as a bi-functional activator to regulate the self-assembly of sericin protein between graphene oxide lamellas, while the sericin-guided NaOH further in situ activates the nanohybrids to produce uniform cellular nanostructures by carbonization. The abundant natural doped nitrogen and oxygen atoms derived from the industry wastes sericin are in-situ maintained after carbonization, which act as polarization centers to promote the attenuation of microwave energy. Benefiting from these merits, the synthesized cellular-like SC/rGO nanohybrids exhibit excellent impedance matching performance, promoted multiple electromagnetic transmission, excellent relaxation polarization phenomenon and microwave absorption properties. The optimized microwave absorption of SC/rGO40-500 reached −53.68 dB at 15.30 GHz, and the effective absorption bandwidth achieved 4.4 GHz (13.35–17.75 GHz) at the thickness of 1.51 mm with a low surface density of 0.035 g/cm2. Our work demonstrates a novel porous structure design strategy on biomass-derived carbon materials as high-efficiency microwave absorbers.