Preparation of a biomass-derived electromagnetic wave absorber with potential EM shielding application in interior decoration surface coating

•Prepare heterostructure bio-carbon from bamboo-derived lignin/cellulose mixture.•Surface modification of graphite-like carbon by lignin-derived carbon particles.•A BC-8 containing coating layer with an effective EM energy attenuation performance.•Enhanced surface hydrophobicity of decoration materials by BC-8 coating.•Mechanism of EMW shielding performance of BC-8 coating layer is explored in depth.