Multifunctional cellular carbon foams derived from chitosan toward self-cleaning, thermal insulation, and highly efficient microwave absorption properties

To adapt the practical demand, designing and constructing the multifunctional microwave absorbers (MAs) is the key future direction of research and development. However, effective integrating the multiple functions into a single material remains a huge challenge. Herein, cellular carbon foams (CCFs) with different porous structures were elaborately designed and fabricated in high efficiency through a facile continuous freeze-drying and carbonization processes using a sustainable biomass chitosan as the precursor. The obtained results revealed that the thermal treated temperature and g-C3N4 amount played a great impact on the carbonization degrees, pore sizes, and morphologies of CCFs, which led to their tunable electromagnetic (EM) parameters, improved conduction loss, and polarization loss abilities. Owing to the special cellular structure, the designed CCFs samples simultaneously displayed the strong absorption capabilities, broad absorption bandwidths, and thin matching thicknesses. Meanwhile, the as-prepared CCFs exhibited the strong hydrophobicity and good thermal insulation, endowing its attractive functions of self-cleaning and thermal insulation. Therefore, our findings not only presented a facile approach to produce different porous structures of CCFs, but also provided an effective strategy to develop multifunctional high-performance MAs on basis of three-dimensional CCFs.