Synthesis of FeNi₃ nanocrystals encapsulated in carbon nanospheres/reduced graphene oxide as a light weight electromagnetic wave absorbent

FeNi₃ nanocrystals encapsulated in carbon nanospheres/reduced graphene oxide (FeNi₃@C@rGO) composites have been synthesized through liquid-phase reduction reaction and then two-step hydrothermal processes followed by a pyrolysis process. The FeNi₃@C and FeNi₃@C@rGO composites were characterized by XRD, SEM, TEM, Raman spectroscopy. SEM shows the FeNi₃ nanocrystals are sphere-like with a rough surface and the average diameter of the particles is about 100 nm. TEM reveals that FeNi₃@C composites with core-shell structures are well distributed on the rGO nanosheets. The paraffin-FeNi₃@C@rGO composite containing only 10 wt% of FeNi₃@C@rGO exhibits excellent electromagnetic wave absorption properties. The maximum R_L value of -47.6 dB is obtained at 10.2 GHz with a layer thickness of 2.6 mm and the absorption bandwidth (R_L < -10 dB) is about 3.12 GHz in the range of 7.28-10.40 GHz for a layer of 3.0 mm thickness. It is believed that FeNi₃@C@rGO can serve as light-weight electromagnetic wave absorbent and can be widely used in practice.