Top-down strategy for bamboo lignocellulose-derived carbon heterostructure with enhanced electromagnetic wave dissipation

Biomass-derived residue carbonization has been an important issue for “carbon fixation” and “zero emission”, and the carbonized products have multiple application potentials. However, there have been no specific research to study the differences in macro- and micro-morphology, electrical properties and many other aspects of the products obtained from carbonization of pure cellulose, pure lignin or their complex, lignocellulose. In this work, lignocellulose with cellulose to lignin mass ratio of 10:1 is obtained using p-toluenesulfonic acid hydrolysis followed by homogenization process at a controlled condition. Then, carbon heterostructure with fibers and sheets (CH-10) are obtained by pyrolysis at 1500 °C. Detailed results imply that the fiber-like carbon structure possesses high crystallinity and low defect density, coming from carbonization of the cellulose content in lignocellulose (LC) nanofibers. Correspondingly, the graphite-like carbon sheet with high defect density and low crystallinity comes from carbonization of the lignin content in LCs. Further investigation indicates CH-10 possesses enhanced polarization and moderate impedance matching which makes it an ideal candidate for electromagnetic wave (EMW) absorption. CH-10 exhibits an excellent EMW absorption performance with a minimum RL value of −50.05 dB and a broadest absorption bandwidth of 4.16 GHz at a coating thickness as thin as 1.3 mm.