Three–dimensional nitrogen-doped porous carbon modified by Co/Ni nanoparticles derived from bimetallic Co/Ni–MOF for enhanced electromagnetic wave absorption

The nitrogen–doped porous carbon (NPC) foam composites modified by magnetic nanoparticles exhibit lightweight properties and excellent impedance matching, making them highly valuable for research and applications in electromagnetic wave shielding and absorption. The present work focuses on binary Co/Ni–MOF as the subject, combining it with carbon foam by adjusting the Co/Ni ratio to obtain various MOF derivatives, thereby exploring their electromagnetic properties. The composite CoNi-2/NPC, yielded through calcinating the precursor CoNi-2/HMT (Co: Ni = 1: 1) at 500 °C, demonstrates excellent wave absorption performance with a low filler content of 15 wt%, achieving a minimum reflection loss of –52.7 dB and an effective absorption bandwidth of 7.36 GHz. The radar cross section (RCS) simulation reveals an RCS reduction of 22.8 dB m² for CoNi-2/NPC. The excellent electromagnetic absorption can be ascribed to the increased interfacial polarization, the improved impedance matching, and defect-induced polarization loss. The present research offers a novel perspective for the design of high–performance electromagnetic absorbing materials featuring a broad absorption bandwidth through controlling their magnetic components.