Graphene-Magnetic Spinel Ferrite Nanocomposite: Facile Synthesis and Excellent Photocatalytic Performance

Spinel ferrite structured ZnFe ₂ O ₄ nanoparticles anchored on reduced graphene oxide (rGO) sheets have been prepared via a facile hydrothermal method combined with a solvothermal approach. For the synthesis of the ZnFe ₂ O ₄ /rGO nanocomposites, the rGO nanosheet contains epoxy functional groups serving as the active sites, which allowed the formation of uniform ZnFe ₂ O ₄ nanoparticles. Due to the structure of the ZnFe ₂ O ₄ /RGO nanocomposites, the aggregation of the ZnFe ₂ O ₄ nanoparticles can be readily disrupted and electronic transfer through the rGO nanosheets is accelerated. This could in turn enhance the photocatalytic efficiency. It was also demonstrated that ZnFe ₂ O ₄ /rGO (40 wt-%) hybrid nanocomposites almost reached adsorption equilibrium in the RhB dye within 60 min. The Langmuir equation model showed that the photodegradation of RhB was well fitted to first order reaction kinetics with k = 0.6254 min ^-1 . This illustrated that the addition of GO could reduce the bandgap of pure ZnFe ₂ O ₄ , which avoided the combination of electrons and holes. The ZnFe ₂ O ₄ /rGO nanocomposites could also enhance the utilisation of sunlight. In addition, the ZnFe ₂ O ₄ /rGO nanocomposite photocatalyst also demonstrated a supramagnetic property, holding potential to be utilised for water treatment.