Comparison of Magnetic, Optical and Morphological Properties of the Nanocomposite of Reduced Graphene Oxide Coated with Zinc Ferrite Synthesized by One-Step Hydrothermal and Two-Step Sol-Gel / Hydrothermal Methods

Reduced graphene oxide coated with zinc ferrite (ZnFe2O4@rGO) nanocomposite was successfully synthesized by the one-step hydrothermal (HT) and the two-step sol-gel/hydrothermal (SG/HT) methods. The results of SEM and TEM images showed that the graphene oxide sheets for HT and SG/HT syntheses had dimensions of 0.3-0.04 μm and 0.7-0.07 μm, respectively,. According to these images, the size of ZnFe2O4 nanoparticles coted on graphene oxide sheets for HT and SG/HT syntheses were observed at 10-40 nm and 25-70 nm, respectively. Comparison of the optical absorption spectrum of ZnFe2O4@rGO nanocomposites synthesized by HT and SG/HT methods revealed that the amount of band gap energy in SG/HT synthesis was about 7% less than from SG/HT synthesis. According to the results obtained from the Raman spectrum for the synthesized graphene oxide sample, the ID/IG ratio was 0.88,. The results of FTIR spectra demonstrated effective reduction of GO as well as composite formation between rGO plates and ZnFe2O4 nanoparticles for both SG/HT and HT synthesis methods. The results of the magnetic properties of ZnFe2O4@rGO nanocomposites synthesized by HT and SG/HT methods by VSM and magnet with 1 T intensity, states that both methods of synthesis produced superparamagnetic materials,. Based on the results of this study, it can be said that for photothermal therapeutic applications which particle size and uniformity of ZnFe2O4@rGO nanocomposites are important, single-step HT method, and for photocatalytic applications and contrast agent in MRI, which need more photocatalytic and magnetic properties, the two-step SG/HT method can be better choice.