▎ 摘　　要

Here a hydrogen-free, solid-pyrolysis of nickel phthalocyanine was developed to produce graphene/carbon nanotube composites doped with 3 -5 at% nitrogen atoms. By changing the nickel ion content in the organometallic precursors, the carbon nanotubes with bamboo-like morphologies, uniformly dispersed on the graphene sheet were obtained in a controlled fashion. The graphene/carbon nanotube composites exhibited a synergistic effect for the microwave absorption properties. A broad absorption bandwidth (RL < -10 dB) of 5.1 GHz (12.9 -18.0 GHz) was achieved with the thickness of 1.5 mm. (c) 2021 Elsevier B.V. All rights reserved.