2 research outputs found
Microporous Co@C Nanoparticles Prepared by Dealloying CoAl@C Precursors: Achieving Strong Wideband Microwave Absorption via Controlling Carbon Shell Thickness
Excellent
magnetic features make Co-based materials promising candidates as
high-performance microwave absorbers. However, it is still a significant
challenge for Co-based absorbers to possess high-intensity and broadband
absorption simultaneously, owing to the lack of dielectric loss and
impedance matching. Herein, microporous Co@C nanoparticles (NPs) with
carbon shell thicknesses ranging from 1.8–4.9 nm have been
successfully synthesized by dealloying CoAl@C precursors. All of the
samples exhibit high microwave absorption performance. The microporous
Co@C sample possessing a carbon shell of 1.8 nm exhibits the highest
absorption intensity among these samples with a minimum reflection
loss (RL) of −141.1 dB, whose absorption bandwidth for RL ≤
−10 dB is 7.3 GHz. As the thickness of the carbon shell increases,
the absorption bandwidth of the NPs becomes wider. For the sample
with the carbon shell thickness of 4.9 nm, the absorption bandwidth
for RL ≤ −10 dB reaches a record high of 13.2 GHz. The
outstanding microwave attenuation properties are attributed to the
dielectric loss of the carbon shell, the magnetic loss of the Co core,
and the cooperation of the core–shell structure and microporous
morphology. The strong wideband microwave absorption of the carbon-coated
microporous Co NPs highlights their potential applications in microwave
absorbing systems