▎ 摘　　要

The uniform growth of monodisperse nickel phosphide nanoparticles on the surface of graphene can greatly enhance the interfacial polarization effect, and makes it an ideal electromagnetic wave (EM) absorbing material. However, the dispersion and size control of nickel phosphide nanoparticles on graphene remains very challenging. In this work, the monodisperse Ni2P nanoparticles had been controllably fabricated and in situ grown uniformly on the surface of reduced graphene oxide (rGO) with the colloidal solution method. The monodisperse mosaic-like nickel phosphide nanoparticles were also obtained by controlling the reaction time and addition amount of rGO. The prepared materials were characterized by the powder XRD, TEM, XPS, Raman and so on. The size of the mosaic large particles and small particles was about 45 and 6 nm, respectively. When this composite was used for EM absorption, excellent EM absorption characteristics in the 2-18 GHz band had been displayed. Its effective EM absorption bandwidth can be up to 3.79 GHz at 1.5 mm thickness, and the minimum reflection loss can be up to -38.3 dB at 2 mm thickness. It could be attributed to the increased EM wave scattering by mosaic large particles in situ grown on rGO, and more interfacial polarization active sites provided by the interface of mosaic small particles and rGO. This unusual hybrid is expected to be a potential candidate for the outstanding EM wave absorption performance.