MOF-derived C/SiOC ceramic aerogels with high strength and excellent microwave absorption performance

Novel MOF-derived C/SiOC composite aerogels were synthesized via a polymer-derived ceramic (PDC) route to achieve superior electromagnetic wave (EMW) absorption, mechanical robustness, and thermal insulation. The Zn/Co species function as efficient catalysts to reduce the graphitization temperature of free carbon, facilitating the formation of conductive networks and defective carbon that enhance dielectric loss. Simultaneously, the in situ construction of multiple heterointerfaces among metal nanoparticles, SiC/SiO₂ nanowires, and the SiOC matrix provides ideal sites for polarization relaxation and multiple scattering. Consequently, the resultant ceramics exhibit exceptional EMW performance, achieving a minimum reflection loss (RL_min) of -62.5 dB and an effective absorption bandwidth (EAB) of 5.32 GHz. Moreover, the material demonstrates robust structural-functional integration, characterized by a compressive strength of 54 MPa and a thermal conductivity of 0.346 W m^-1 K^-1. This work underscores a strategic approach to designing multifunctional SiOC-based absorbers for extreme environments.