A self-assembly of graphene oxide@Fe₃O₄/metallo-phthalocyanine nanohybrid materials: synthesis, characterization, dielectric and thermal properties

In this work, we report the synthesis of novel inorganic–organic hybrid nanomaterials (GO@Fe₃O₄ /CuPc) and GO@Fe₃O₄ /ZnPc) consisting of sheets of graphene oxide (GO) decorated by iron oxide nanoparticles (Fe₃O₄), the whole heterostructure functionalized with metallo-phthalocyanines (MPc, M≡Cu or Zn). First the synthesis of nanomaterial (GO@Fe₃O₄) was prepared by hydrothermal self-assembly process through the mixture of graphene oxide and Fe⁺²/Fe⁺³ salt solution. The metallo-phthalocyanines anchorage on the surface of nanosystem was lately performed by facile and effective ultrasonication method. The structure, composition and morphology of nanohybrids and intermediates were investigated by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, UV–visible spectroscopy, scanning and transmission electron microscopy and impedance spectroscopy. All the results suggested that iron-based nanoparticles were successfully deposited onto graphene oxide sheet networks in the form of Fe₃O₄, forming nanospheres, decreasing in lattice defects of the GO sheets and dramatically increasing the dielectric properties of nanosystems. Nanomaterials presented saturation magnetization in the 52–58 emu/g and superparamagnetic behavior. It was observed that the values of dielectric constant decreased as a function of the amount of phthalocyanines in the nanomaterials. Therefore, because of their versatile magnetic and dielectric performances, the novel superparamagnetic hybrid nanomaterials, herein described, can be considered as potential for microwave devices.