Preparation of CNFs/RGO/CuS Composite Materials with Porous Structure and Excellent Microwave Absorption Performance

Abstract

In this study, green cellulose nanofibers-based composites were successfully prepared for efficient wide-band electromagnetic absorber to realize functional and high-value diversified utilization of cellulose nanofibers. Specifically, by the introduction of reduced graphene oxide (RGO) and flower-like copper sulfide (CuS) into CNFs used as raw material, CNFs/RGO/CuS porous composite microwave absorber were obtained. The CNFs/RGO/CuS porous composite exhibited excellent microwave absorption performance due to its unique three-dimensional porous flower-like structure and heterogeneous interface, which provided excellent impedance matching and attenuation capabilities. The fabricated CNFs/RGO/CuS composite exhibited a minimum reflection loss (RLmin) of [Formula: see text]49.71[Formula: see text]dB at 11.52 GHz and a maximum absorption bandwidth of 5.30 GHz (from 10.40 GHz to 15.70 GHz) at only 2.50[Formula: see text]mm. In addition, the scanning electron microscope (SEM) results showed that the CNFs/RGO/CuS composite had a porous microstructure. And the Brunauer–Emmett–Teller (BET) specific surface area of the CNFs/RGO/CuS composite was 326.46[Formula: see text]m2/g. Potential absorption mechanisms were proposed considering the interfacial polarization, impedance matching, and dielectric losses caused by the synergistic effects among CNFs, RGO, and CuS. This work proposed a new strategy to biomass-based functional materials, and used the natural polymer CNFs, compounded with reduced graphene oxide and copper sulfide, to achieve efficient microwave absorbing materials.