Ternary nanocomposites of graphene@SiO 2 @NiO nanoflowers: synthesis and their microwave electromagnetic properties

The ternary composites of graphene@SiO 2 @NiO nanoflowers were fabricated by a multi‐step route. Graphene oxide (GO)@SiO 2 sheets were formed by a layer of silica nanosheets coated on the surface of GO. Then, GO@SiO 2 sheets were introduced as substrates for the growth of NiO nanoflowers. The microwave absorption property of the ternary composites was studied in the frequency ranging from 2 to 18 GHz, and the effect of the thickness of the ternary composites on microwave absorption was also investigated. The results indicate that graphene@SiO 2 @NiO nanoflowers composites exhibit enhanced microwave absorption compared with graphene@SiO 2 . The reflection loss of graphene@SiO 2 @NiO nanoflowers below −10 dB is 5 GHz (from 10 to 15 GHz) and the maximum absorption is −20.5 dB at 11.3 GHz with a thickness of 3 mm.