Metal-organic framework derived magnetic carbon Ni@C octahedron composite as an excellent microwave absorber

Metal-organic framework (MOF)-derived magnetic carbon composites have become ideal candidates as high-performance microwave-absorbing materials. Herein, the MOF-derived Ni@C octahedron composite was synthesized via a facile solvothermal reaction and annealing treatment, which involved a material transition process from the Ni-MOF into the magnetic Ni@C composite. The structural, morphological, magnetic, and electromagnetic (EM) properties of as-prepared MOF-derived Ni@C materials were determined. Given the MOF template and controlled carbonized treatment, the obtained micro-scale Ni@C octahedron showed adjustable EM parameters and EM wave absorption property by adjusting the addition amount. The optimized reflection loss value of MOF-derived Ni@C reached -51.9 dB at 10.5 GHz at 2.5 mm thickness, and the composite had broadband microwave attenuation and covered 5.6 GHz from 8.9 GHz to 14.5 GHz. Given the good impedance matching, special spatial structure, and synergy effect between magnetic and dielectric losses, this MOF-derived magnetic carbon Ni@C octahedron composite is expected to be a potential EM wave-absorbing material.