In situ synthesis hydrophobic Co/CoO/C nanofibers with enhanced microwave absorption

Abstract

Carbon nanofiber composites could be used as a microwave absorbing candidate owing to its lightweight and dielectric properties. In this work, the carbon-based nanofibers were synthesized using cobalt acetate tetrahydrate (CoAc)/poly (vinyl alcohol) (PVA) as a precursor solution via the electrospinning and vacuum carbonization at 650 °C. Co and CoO were simultaneously introduced into carbon nanofibers (CNFs). The CNFs absorber with an especially low filling ratio of 10% exhibited excellent microwave absorbing properties. The minimum reflection loss (RL) reached −43.57 dB at 10.48 GHz with a matching thickness of 3 mm, and the wideband effective absorption (RL ≤ −10 dB) reached 5.78 GHz (10.94–16.72 GHz) at 2.5 mm. The superior absorption performance of the as-prepared CNFs resulted from the formation of CoO, causing the improvement of impedance matching and interfacial polarization. Besides, the CNFs displayed good hydrophobicity due to the roughened surfaces. These newly synthesized Co/CoO/CNFs might be considered as a prospective candidate for highly efficient microwave absorption materials with a self-cleaning function.