▎ 摘　　要

Boron carbide (B4C) is normally known as a structural ceramic with excellent mechanical properties. Herein, the application of graphene-layer-coated B4C nanosheets (B4C@GN NSs) as efficient electromagnetic (EM) wave absorption materials was reported for the first time. B4C@GN NSs grew via the vapor-solid (VS) mechanism and coated with an ultrathin graphene layer through annealing. In addition to its graphene shell, the B4C@GN NSs had a unique small-sized nanosheet structure with a single sheet thickness of less than 50 nm. Concurrently, B4C micro- and nanoparticles were purchased or prepared to compare the morphologies and performances of several kinds of different B4C materials via characterization and analyses. The comparison revealed that the novel B4C@GN NSs possessed a special structure and a unique graphene shell that led to the great improvement in EM wave absorption. With a thickness of 1.19 mm, the B4C@GN NSs exhibited a minimal reflection loss (RLmin) of 24.6 dB and a broad effective absorption bandwidth of 3.9 GHz. The electronic structure was analyzed by XANES to clarify the mechanism. The above results proved B4C@GN NSs to be an expectant absorber. The development of B4C@GN NSs might lay a theoretical foundation for the functionalization of structural ceramic materials.