Abstract:

Recently, developing carbon-based hybrid materials loaded with magnetic components has been generally regarded as a promising and practically feasible strategy when it comes to constructing lightweight electromagnetic wave absorbers. In the current work, reclaimed carbon black (CB) nanopowder was firstly produced by simple burning of wheat straw, which was then employed as sustainable carbon-based host materials (carrier) and successfully decorated Co@C nanoparticles via a simple thermal reduction process. Remarkably, both the as-fabricated nanocomposites and corresponding electromagnetic wave absorption performances could be effectively tuned by tailoring the dosage of the Co@C nanoparticles. The minimum reflection loss (RL_min) of -53.989 dB was achieved for CB/Co@C-2# at 2.28 mm thickness, meanwhile, CB/Co@C-3# was featured by a wide effective absorption band (EAB) of 6 GHz (6.72-12.72 GHz) at a 2.73 mm matching thickness, which covered the entire X band, suggesting that the CB/Co@C nanocomposites were an attractive candidate for electromagnetic wave absorber. According to the synergistic influence of dielectric loss and magnetic loss from CB and Co@C, respectively, as well as the properly matched impedance, a reasonable electromagnetic wave attenuation mechanism was illustrated. It is noteworthy that the preparation process of CB is a facile, recycled, and low-cost strategy for achieving nanoscale carbon-based absorbing materials, moreover, the CB/Co@C nanocomposites provide a reference for constructing lightweight dielectric-magnetic products with superb electromagnetic wave absorption performances.

Key words: Reclaimed carbon black, Microwave absorption, Attenuation mechanism, Preparation technique, CB/Co@C nanocomposites