Activating microwave absorption performance by reduced graphene oxide-borophene heterostructure

Abstract

Reduced graphene oxide (RGO) nanosheets normally possess large specific surface area, good electrical conductivity, and low density, but their unsatisfactory intrinsic complex permittivity and poor impedance matching severely hinder the further application in microwave adsorption. In this work, borophene nanosheets (BNS), the lightest 2D material, are proposed as an efficient activator to improve the microwave absorbing performance on RGO. BNS are assembled and immobilized on RGO surface through the interfacial covalent interaction, to construct a new metal-free 2D hybrid absorbent. These incorporated BNS serves as the joining site and channel in the framework to facilitate electrons hopping and migration between RGO layers. As a result, conductive loss mechanism is well enhanced, which is the major contribution to its dielectric property, conferring high impedance matching on the absorbent. As expected, the as-obtained 2D metal-free hybrid demonstrates microwave absorbing parameters that approach those of the most active absorbents, with the minimum reflection loss reaching −53.3 dB and the broadest effective absorption bandwidth of 6.16 GHz, at a low filler loading of 3 wt%.