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 (<−10 dB) was as high as 8.54 GHz with a low filler ratio of 10 wt% at the thickness of 5 mm. Hence, these lightweight and broadband MOFs-derived nanocomposites are highly promising for applications requiring excellent microwave absorption performance.