Integrating large specific surface area and tunable magnetic loss in Fe@C composites for lightweight and high-efficiency electromagnetic wave absorption

Abstract

Porous Carbon-based composites with large specific surface area are promising as lightweight electromagnetic wave (EMW) absorbers due to their inherently rich interfaces that facilitate microwave attenuation. However, the exertion of the intrinsic advantage of large surface area was underexplored. Herein, we described a facile strategy using MOF-derived large surface area porous carbon to construct dielectric-magnetic composites for high-efficiency EMW absorbers. In particular, a series of Fe@C composites were fabricated by pyrolysis of MOF-5 to form porous carbon matrix (SBET ∼ 1800 m2/g), followed by ferrocene deposition and reduction. By altering Fe species amount, surface area and electromagnetic parameters of the composites were tuned. It is found Fe@C-0.6 composites with sufficiently high SBET ∼915.8 m2/g exhibited outstanding microwave absorption performance with the minimum reflection loss (RLmin) of −64.6 dB (1.98 mm thickness and 15 wt% loading) and the effective absorption bandwidth (EAB) up to 6.27 GHz (2.2 mm thickness). Besides, Fe@C-1 (SBET ∼820.1 m2/g) also achieved desirable loss capability, with EAB covering the whole Ku band. This work demonstrates the potential of high surface area to achieve optimal EMW attenuation, and may provide a facile alternative to develop more high-performance carbon composites for EMW absorption application.