In Situ Fabrication of Heterogeneous Co/Nanoporous Carbon Nano-Islands for Excellent Electromagnetic Wave Absorption.

High-performance electromagnetic wave (EMW) absorbers are essential for addressing electromagnetic pollution and military security. However, challenges remain in realizing cost-effectiveness and modulating absorbing properties. In this study, heterogeneous Co/nanoporous carbon (NPC) nano-islands are prepared by efficient method co-precipitation combined with in situ pyrolysis. The multi-regulation strategy of morphology, graphitization, and defect density is achieved by modulating the pyrolysis temperature. Adjusting the pyrolysis temperature can effectively balance the conductivity and defect density, optimizing the impedance matching and enhancing the attenuation. Furthermore, it facilitates obtaining the appropriate shape and size of Co magnetic nanoparticles (Co-MNPs), triggering strong surface plasmon resonance. This resonance, in turn, bolsters the synergy of dielectric and magnetic loss. The incorporation of porous nanostructures not only optimizes impedance matching and enhances multiple reflections but also improves interfacial polarization. Additionally, the presence of enriched defects and heteroatom doping significantly enhances dipole polarization. Notably, the absorber exhibits an impressive minimum reflection loss (RL) of -73.87 dB and a maximum effective absorption bandwidth (EAB) of 6.64 GHz. The combination of efficient fabrication methods, a performance regulation strategy through pyrolysis temperature modulation, and radar cross section (RCS) simulation provides a high-performance EMW absorber and can pave the way for large-scale applications.