Synthesis and enhanced electromagnetic absorption properties of Co-doped CeO2/RGO nanocomposites

Highlights: • Co-doped CeO₂/RGO nanocomposites were prepared by simple hydrothermal method. • The absorbing properties would alter with the change of Co²⁺/Ce³⁺ added molar ratio. • Co-doped CeO₂/RGO nanocomposites showed promising microwave absorption performance. • The minimum reflection loss of Co-doped CeO₂/RGO was −53.66 dB at 6.4 GHz. Co-doped CeO₂/reduced graphene oxide (RGO) nanocomposites were prepared successfully by a simple solvothermal method using cobalt nitrate, cerium nitrate, and graphene oxide. The structure, micromorphology, material composition, and electromagnetic properties of the nanocomposites were investigated by X-ray Power diffraction, X-ray photoelectron spectroscope, transmission electron microscope, and vector network analyzer. The microwave absorption performance of nanocomposite in 2–18 GHz was calculated in accordance with transmission line theory. These results suggest that Co-doped CeO₂/RGO composites do not influence the cubic fluorite structure of CeO₂ and that Co-doped CeO₂ nanoparticles were densely attached onto the RGO sheets (GSs). The Co-doped CeO₂/RGO composites also enhanced microwave absorption properties owing to the synergetic effect between the Co-doped CeO₂ nanoparticles and GSs and the unique structure of CeO₂. When the added molar ratio of Co(NO₃)₂·6H₂O and Ce(NO₃)₃·6H₂O was 1:6, the composites attained the optimal microwave absorption of −53.66 dB at 6.4 GHz under the coating thickness of 3.5 mm. By contrast, frequency bandwidths below −10 and −20 dB were 4 and 1.28 GHz, respectively, under the coating thickness of 2.0 mm.