In situ-derived carbon nanotube-decorated nitrogen-doped carbon-coated nickel hybrids from MOF/melamine for efficient electromagnetic wave absorption

Carbon nanotube-decorated nitrogen-doped carbon-coated nickel (CNT/Ni@N-C) microspheres have been fabricated by pyrolyzing the mixture of nickel-based metal organic framework (Ni-MOF) and melamine. The resultant composite is assembled from CNTs and spherical Ni@N-C composite. Besides, the CNT/Ni@N-C composite contains abundant nitrogen (N) dopants that contribute to defect dipole polarization. The melamine content is important for controlling the amount of N element and N dopant state in the composite. The optimized CNT/Ni@N-C composite with high content of pyridinic N exhibits strong absorption of -55.1 dB at 10.56 GHz with the thickness of 2.5 mm, and the effective absorbing bandwidth (reflection loss < -10 dB) is 11.2 GHz (6.0-17.2 GHz) with the thickness range of 1.5-4.0 mm. These results indicate that the N content and N dopant state have a great influence on electromagnetic wave absorption properties. This strategy will contribute to fabricate the carbon hybrid network consisting of metal organic frameworks derived metal/carbon hybrid and CNTs for electromagnetic wave absorption.