3D porous Ni@BPC composites for enhanced electromagnetic wave absorption

Using biomass as raw material to prepare porous carbon (BPC) through a simple heat treatment process is an environmentally friendly and economically feasible method to deal with electromagnetic pollution. In this work, a porous Ni@BPC-based composite material is synthesized using laver as raw materials, where the Ni nanometer microspheres are evenly distributed in BPC. Herein, the electromagnetic parameters of the composites are effectively tuned by the combination of magnetic Ni with dielectric BPC. The synthesized composite with 3D porous structure exhibit remarkable enhancement of microwave absorption. Results showed that when the mass ratio of Ni to BPC is 1:3, the minimum reflection loss (RL) of porous Ni@BPC composite reaches - 35.73 dB at 3.0 mm with the effective absorption bandwidth (RL < -10 dB) of 6.37 GHz (from 10.35 to 16.72 GHz) at 2.5 mm. It is believed that the excellent microwave absorption properties are attributed to the enhanced synergistic effect of the losses, such as conductive loss, interfacial polarization, natural resonance, exchange resonance and multiple scattering. It is proved that the porous Ni@BPC composite exhibits potential applications in microwave absorption.(c) 2022 Elsevier B.V. All rights reserved.