Hierarchical Porous Carbon/Co Nanocomposites Derived from Biomass for High-Performance Microwave Absorption

Biomass-derived carbon materials have attracted considerable attention in electromagnetic wave (EMW) absorption applications due to their advantages of low cost, light weight, and sustainability. Herein, loofah sponge-derived hierarchical porous carbon nanocomposites (HPC/Co-T) were successfully synthesized by a facile dipping and subsequent carbonization method. The combination of hierarchical porous carbon with magnetic Co nanoparticles takes advantage of the synergistic effect of dielectric loss and magnetic loss, which is a compelling route to improve impedance matching and EMW attenuation capacity. The specific surface area, carbon defects, and electromagnetic parameters of the HPC/Co-T nanocomposites are effectively regulated through carbonization temperature. The HPC/Co-700 nanocomposite annealed at 700 °C with a filler content of 15 wt % exhibits an RL_min value of −66.8 dB at a thickness of 2.4 mm. Meanwhile, a broad effective absorption bandwidth of 5.5 GHz ranging from 11.7 to 17.2 GHz can be achieved at a thickness of 2.1 mm. This work provides a strategy for the fabrication of low-cost, sustainable, lightweight, and high-performance EMW-absorbing materials from nature biomass.