▎ 摘　　要

A two-step method has been adopted to synthesize cobalt nanoclusters in carbon (CoC)-decorated reduced graphene oxide (rGO) from graphene oxide (GO) and ZIF-67 as an excellent stable electromagnetic wave (EMW) absorber. Firstly, the electrostatic force between GO and Co2+ gave rise to in situ growth of ZIF-67 on GO (ZIF-67-GO). Then CoC-rGO was obtained by calcination of ZIF-67-GO hybrids. The ligand is introduced as the nitrogen source to GO. The crystal structure, chemical composition, and magnetic properties of CoC-rGO were investigated by x-ray powder diffraction analysis, Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and vibrating-sample magnetometry. The morphology was observed by scanning electron microscopy and transmission electron microscopy. By adjusting the ratio of GO to ZIF-67, the electromagnetic parameters of CoC-rGO can be optimized. It was found that the sample consisting of 10 wt.% CoC-rGO-2 in a paraffin matrix exhibited excellent EMW absorption performance, reaching a minimum reflection loss (RLmin) of -44.77 dB with thickness of 2.1 mm and an effective bandwidth (RL