Enhancing electromagnetic wave absorption and hydrophobicity/heat insulation properties of coral-like Co/CoO/RGO aerogels through pore structure regulation.

To optimize the electromagnetic wave performance for absorbers, it is crucial to implement rational structural designs and integrate multiple loss modes in a coordinated manner. Here, three-dimensional (3D) porous macroscopic coral-like Co/CoO/reduced graphene oxide aerogels (Co/CoO/RGO), are successfully fabricated by an ice-templated freeze-drying and thermal reduction techniques, and their pore structures, involving aperture and total pore volume, are availably regulated by manipulating the water addition. The electromagnetic parameters and electromagnetic wave performance appear strong response toward the variation of pore structure. By controlling the pore structure, these parameters can be efficaciously tunned, thus manipulating the performance. The optimized absorption performance is obtained when the water addition is 1 ml, the minimum reflection loss reaches to −61.8 dB and the effective bandwidth is 4.2 GHz. Such good performance is inseparable with the 3D crosslinked conductive framework, the hybrid of magnetic and dielectric units, numerous heterointerfaces and countless pores walls in aerogels, which brings multiple electromagnetic wave loss mechanism. Moreover, it is very important that Co/CoO/RGO aerogels also integrate good hydrophobicity and heat insulation properties, allowing their application in harsh conditions. This work shows the potential of pore structural control engineering for producing multifunctional aerogels. [Display omitted] • Co/CoO/RGO aerogels with porous interconnected framework are successfully fabricated. • The porous network creates numerous heterointerfaces, and establish conductive pathways. • Good EM wave absorption property is achieved via the integration dielectric and magnetic components. • The minimum reflection loss and the effective bandwidth reaches to −61.8 dB and 4.2 GHz respectively. • The material exhibits multifunction, e.g., good EM wave absorption, hydrophobic and heat insulation properties. [ABSTRACT FROM AUTHOR]