Ni-MOF nanorods derived graphitic carbon encapsulated Sub-10 nm Ni particles for boosting dielectric polarization and efficient electromagnetic wave absorption

Particle size goes down from microns to nano and sub-nano present special electricity and magnetism characteristics, thus it will affect its electromagnetic wave absorption performance. But this effect needs to be studied further. In this work, we innovatively synthesized nanorod-like Ni-MOF by one-step hydrothermal method, followed by pyrolysising Ni-MOF to obtain the composites of Ni nanoparticles and graphitic carbon (Ni/GC), and then acid etching the bulk nanoparticles on the graphene surface to obtain graphitic carbon encapsulated sub-10 nm Ni particles (S-Ni/GC). The S-Ni/GC shows great feasibility in electromagnetic wave absorption than Ni/GC. The strongest reflection loss of S-Ni/GC can achieve -54 dB with the thickness of 2.3 mm, the absorption bandwidth below -10 dB is 11.68 GHz only with the 5 % filler content in paraffin-sample. The sub-10 nm size Ni nanoparticles after etching greatly improved wave absorption performance attributed to the uniform magnetdielectric network and increased dielectric polarization.