Environmentally friendly bark-derived Co-Doped porous carbon composites for microwave absorption

Biomass-derived porous carbon has attracted tremendous attention in many research fields due to its cheap and feasible strategy. In this work, bark-derived Co-doped porous carbon composites (Co@PC) for microwave absorption (MA) applications were successfully prepared through a simple method. The minimum reflection loss (RLmin) of Co@PC (carbonized at 800 degrees C, Co2+ concentration is 0.15 molL(-1)) is -49.2 dB at 10 GHz and a wide effective absorption bandwidth (EAB) of 6.16 GHz was obtained. Further, by adjusting carbonization temperature of the bark, the MA performance could be further enhanced. The results show that the RLmin could be -58.4 dB at 8.6 GHz when the bark was carbonized at 900 degrees C. The retained channel structures of the bark played an important role in this excellent MA performance, which is not only cause multiple reflections and scattering of microwaves, but also benefit to the impedance matching. Cobalt-nanoparticles (Co-NPs) dispersed on the surface of the channel structures, endow a strong magnetic loss of microwave energies. In addition, radar cross section (RCS) simulation results also demonstrate that Co@PC can be applied in the field of microwave absorbing materials (MAMs). (C) 2021 Published by Elsevier Ltd.