Fabrication of single-crystal porous hedgehog-sphere structured TiO2–rGO aerogel as a strong broadband electromagnetic wave absorber

Abstract

Excessive conductivity of graphene oxide (GO) often contributes to the inferior impedance matching performance of the material, which imposes extreme restrictions on the field of electromagnetic wave (EMW) absorption. A highly fruitful strategy to ensure that the material possesses both distinguished EMW attenuation and impedance matching capabilities is to combine GO with some other substances with low conductivity. In this study, TiO₂ microspheres with a single-crystal mesoporous hedgehog-ball structure are fabricated and anchored on GO nanosheets via a facile hydrothermal strategy. The electromagnetic parameters of the composites are regulated through adjusting the mass ratio of TiO₂ to GO, and thereby precisely regulating the EMW absorbing properties. Consequently, the fabricated TiO₂–rGO 1 : 1 sample exhibits prominent EMW absorption capacity with a broad effective absorption bandwidth (EAB) of 8.08 GHz and strong reflection loss (RL_min) of −44.7 dB. The extraordinary EMW absorption performance is attributed to the synergistic effect of TiO₂ and GO, including abundant conduction loss and polarization loss. In addition, quantitative analyses of conduction loss and polarization loss of the fabricated composites are conducted to provide clear guidance for our future work. This work not only provides guidance and inspiration for the structural design of EMW absorbers but also discloses the relationship between conduction loss and polarization loss of materials.