posted on 2023-12-13, 03:43authored byMengyi Zhang, Xiaohui Sun, Xudong Cai, Xiaolu Zhan, Yufei Wu, Xuyang Zhang, Guohua Wu, Xiangwei Wang
In
the field of electromagnetic wave (EMW) absorption, carbon matrix
materials based on metal–organic frameworks (MOFs) have drawn
more interest as a result of their outstanding advantages, such as
porous structure, lightweight, controlled morphology, etc. However,
how to broaden the effective absorption bandwidth [EAB; reflection
loss (RL) ≤ −10 dB] is still a challenge. In this paper,
large microsphere structures of a Co/C composite composed of small
particle clusters were successfully prepared by the solvothermal method
and annealing treatment. At a filling ratio of 40 wt %, the Co/C composite
shows attractive microwave absorption (MA) performance after being
annealed at 600 °C in an atmosphere of argon. With an EAB of
6.32 GHz (9.92–16.24 GHz) and a thickness of just 2.57 mm,
the minimum RL can be attained at −54.55 dB. Most importantly,
the EAB can attain 7.12 GHz (10.88–18.0 GHz) when the thickness
is 2.38 mm, which is larger than that of the majority of MOF-derived
composites. The superior MA performance is strongly related to excellent
impedance matching and a higher attenuation constant. This study provides
a simple strategy for synthesizing a MOF-derived Co/C composite with
a wide EAB.