Structure-controlled Ni@N-doped Porous Carbon/Carbon Nanotube Nanocomposites Derived from Metal-Organic Frameworks with Excellent Microwave Absorption Performance

Abstract Structure-controlled nickel @nitrogen-doped porous carbon/carbon nanotube (Ni@NC/CNT) nanocomposites derived from metal−organic frameworks (MOFs) were successfully synthesized via sintering Zn-Ni precursor under the nitrogen atmosphere. Appropriately regulating the molar ratio of Zn-Ni could effectively control the content and length of CNTs and realize unique structures, as demonstrated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy characterization. According to the vector network analyzer test, Ni@NC/CNT nanocomposites displayed outstanding electromagnetic wave absorption performance, which can be attributed to magnetic-dielectric synergy effect, impedance matching, multifarious transmission paths, interface polarization and dipole polarization between Ni nanoparticles (NPs), N-doped porous carbon shell and CNTs. Surprisingly, when the molar ratio of Zn-Ni was 1:3, the maximum reflection loss (RL) of the optimized nickel @nitrogen-doped porous carbon/carbon nanotube-1/3 (Ni@NC/CNT-1/3) nanocomposite reached up to -74.06 dB at 15.63 GHz with a matching thickness of only 1.911 mm. Furthermore, the largest effective absorption band width (