Biomass-derived Co@crystalline carbon@carbon aerogel composite with enhanced thermal stability and strong microwave absorption performance

A novel Co@crystalline carbon@carbon aerogel composite with yolk-shell structure was fabricated via a green and facile method using biomass-based alginate aerogels as precursor. In the resultant composite, a large amount of highly crystallized Co nanoparticles (similar to 41.5 wt%) with a diameter of 5-20 nm was coated with crystalline carbon layer and evenly embedded in the porous carbon aerogel matrix. Due to core-shell Co@crystalline carbon structure, the thermal oxidation stability of the composite can be significantly improved. The porous composite also had the high surface area (425 cm(3) g(-1)) and showed considerable magnetization. Benefitting from the well-designed constitution and structure, the Co@crystalline carbon@carbon aerogel composite showed great microwave absorption performances. When the filler loading of the composite in wax was only 10 wt% and the thickness of the absorber was as thin as 1.5 mm, the maximum RL reached -43 dB. The excellent microwave absorption performances with low filler loading and ultrathin thickness make the aerogel composite show great potential application in the microwave absorption field. (C) 2017 Elsevier B.V. All rights reserved.