Embedding Multiple Magnetic Components in Carbon Nanostructures via Metal-Oxo Cluster Precursor for High-Efficiency Low-/Middle-Frequency Electromagnetic Wave Absorption.

With the advent of wireless technology, magnetic-carbon composites with strong electromagnetic wave (EMW) absorption capability in low-/middle-frequency range are highly desirable. However, it remains challenging for rational construction of such absorbers bearing multiple magnetic components that show uniform distribution and favorable magnetic loss. Herein, a facile metal-oxo cluster (MOC) precursor strategy is presented to produce high-efficiency magnetic carbon composites. Nanosized MOC Fe shelled with organic ligands is employed as a novel magnetic precursor, thus allowing in situ formation and uniform deposition of multicomponent magnetic Fe/FeO@FeC and Fe/FeO nanoparticles on graphene oxides (GOs) and carbon nanotubes (CNTs), respectively. Owing to the good dispersity and efficient magnetic-dielectric synergy, quaternary Fe/FeO@FeC-GO exhibits strong low-frequency absorption with RL of -53.5 dB at C-band and absorption bandwidth covering 3.44 GHz, while ultrahigh RL of -73.2 dB is achieved at X-band for ternary Fe/FeO-CNT. The high performance for quaternary and ternary composites is further supported by the optimal specific EMW absorption performance (-15.7 dB mm and -31.8 dB mm) and radar cross-section reduction (21.72 dB m and 34.37 dB m). This work provides a new avenue for developing lightweight low-/middle-frequency EMW absorbers, and will inspire the investigation of more advanced EMW absorbers with multiple magnetic components and regulated microstructures.