Multiple reflection and scattering effects of the lotus seedpod-based activated carbon decorated with Co3O4 microwave absorbent

The lotus seedpod-based activated carbon (LSAC) is derived from pyrolysis of lotus seedpod as biomass carbon precursor, and Co3O4 is then deposited to LSAC by oxidation-precipitation and crystallization process of Co ions from Co(NO3)(2) solution. The Co3O4 particles uniformly decorate on the surface and/or the inner channels of LSAC. The optimal reflection loss (RL) value of LSAC/Co3O4-paraffin wax (PW) composite reaches similar to 39.8 dB, and the bandwidth for RL below similar to 10 dB and similar to 20 dB are 10.3 and 3.0 GHz, respectively, much better than that of LSAC-PW composite for the higher magnetic loss. The addition of Co3O4 particles in LSAC-PW composite significantly enhance the RL values in various thicknesses. The channels of the LSAC and decorated Co3O4 can improve the abilities of multiple scattering, dipole polarization, interface polarization and magnetic loss. This composite provides a promising method to construct high performance absorbers by using biomass carbon to tune the dielectric properties of the ferromagnetic materials. (C) 2021 Elsevier Inc. All rights reserved.