Enhanced electromagnetic wave absorption performance of ZnO/N-doped carbon microspheres in 2–18 GHz

The properties of popular absorbing materials include low thickness, lightweight, a wide frequency range of absorption, and a significant absorption capacity. However, synthesizing a material that contains all these properties remain a considerable challenge. In this manuscript, Zn, N, O-doped microspheres precursors were innovatively synthesized using the one-pot method, which was efficient and simple. Zn, N, O-doped carbon composites (ZnO/N-CNs) were synthesized by heating precursors in an Ar atmosphere. The electromagnetic wave absorption (EMWA) performances for the composites were modified by altering the calcination temperature of the precursors. As a result, the performance of the ZnO/N-CNs calcined at 700 °C (ZnO/N-CNs-700) in electromagnetic wave absorption (EMWA) was outstanding. The effective absorption bandwidth (EAB) attained 5.68 GHz (12.32–18 GHz, 2.08 mm), while the minimum reflection loss (RLmin) achieved −44.6 dB (12.24 GHz, 2.5 mm). The synergistic interaction of the porous structure, ZnO/C heterostructure, ZnO particles, carbon, and nitrogen was responsible for the superior EMWA properties of ZnO/N-CNs composites. Therefore, the composites exhibited improved interface and dipole polarization loss, conduction loss, multiple reflection and scattering, and impedance matching. This technique made it possible to mass-produce brand-new N-doped carbon-based composites, which had effective EMWA performance. This article suggested a practical method for creating dielectric wave-absorbing composites with excellent all-around performances.