Facile Fabrication of Extremely Small CoNi/C Core/Shell Nanoparticles for Efficient Microwave Absorber.

CoNi magnetic nanoparticles (NPs) and hybrid architectures have attracted tremendous attention from numerous applications. In this study, a facile approach based on one-step metal-organic chemical vapor deposition (MOCVD) was developed to fabricate CoNi/C core/shell NPs with an extremely small core size of ∼ 3.7 nm and an ultrathin shell thickness of 1–3 nm. Only 10 wt.% CoNi/C core/shell NP-filled composites with thickness of 1.6 mm exhibit an optimal reflection loss value of − 25.7 dB and an absorbing bandwidth value up to 6.2 GHz. The extremely small core/shell NPs are demonstrated to have enhanced electromagnetic parameters (i.e., complex permittivity and permeability), reflection loss and broadened effective absorption bandwidth, as compared to the relatively larger NPs. The superior microwave absorbing performance should be attributed to the increased specific area with enriched interfacial polarization. The as-synthesized extremely small CoNi/C core/shell NPs are expected to be a fascinating candidate for efficient microwave absorption material with lightweight and thin thickness. A facile approach based on one-step metal–organic chemical vapor deposition was developed to fabricate CoNi/C core/shell nanoparticles with an extremely small core size of ∼ 3.7 nm and an ultrathin shell thick of 1–3 nm. An optimal reflection loss of –25.7 dB and absorbing bandwidth up to 6.2 GHz could be achieved for CoNi/C nanoparticle-loaded composites with thickness of 1.6 mm, which demonstrated to be a fascinating candidate for efficient microwave absorber with lightweight and thin thickness. [ABSTRACT FROM AUTHOR]